Lenz Law and Conservation of Energy
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Lenz Law and Conservation of Energy

Understand the direction of induced current, the negative sign in Faraday's law and how electromagnetic induction obeys conservation of energy.

Lenz LawInduced Current DirectionFleming Right Hand RuleConservation of EnergyMoving Magnet ProblemsConducting Loop ProblemsNumericalsPYQs

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1. Introduction

Lenz Law tells the direction of induced current in electromagnetic induction. It is important because Faraday's law gives the magnitude of induced EMF, but Lenz Law gives the direction. The induced current always acts in a way that opposes the change in magnetic flux responsible for producing it.

2. Statement of Lenz Law

The direction of induced current is always such that it opposes the change in magnetic flux that produces it. It opposes the change, not necessarily the magnetic field itself.

Faraday-Lenz Lawe = −dΦ/dt
For N turnse = −N dΦ/dt
Meaning of negative signopposition to flux change

Flux increases

Induced current tries to decrease it.

Flux decreases

Induced current tries to increase it.

3. Lenz Law with Moving Magnet and Coil

Four correct Lenz Law magnet-coil cases
1. North pole approaches N G Coil face near magnet: North Opposes approaching north pole. 2. North pole moves away N G Coil face near magnet: South Attracts receding north pole. 3. South pole approaches S G Coil face near magnet: South Opposes approaching south pole. 4. South pole moves away S G Coil face near magnet: North Attracts receding south pole.

4. Galvanometer Animation

Current flows only when magnetic flux changes. If the magnet is at rest, there is no flux change and no induced current.

Galvanometer deflection depends on flux change
NS G motion changes flux towards: deflection one side rest: no deflection away: opposite deflection

5. Fleming's Right Hand Rule

Fleming's Right Hand Rule is used to determine the direction of induced current when a conductor moves in a magnetic field. Thumb shows motion, first finger shows magnetic field and second finger shows induced current.

Fleming's Right Hand Rule
Thumb: Motion First finger: B Second finger: Current Use for conductor-motion cases. Lenz Law explains opposing nature.

Lenz Law

Explains the opposing nature of induced current.

Fleming Rule

Gives direction in conductor-motion generator cases.

6. Conservation of Energy in Lenz Law

If induced current supported the change in flux instead of opposing it, energy would be created from nothing. Therefore nature makes the induced current oppose the cause producing it.

Energy conversionMechanical Energy → Electrical Energy → Heat Energy

7. Mathematical Derivation of Energy Conservation

Conducting rod energy conservation
×××××××××××××××××××××××××××××××××××××××××× v induced force opposes motion R Pmech = Fv = B²l²v²/R = I²R = Pelec
Motional EMFe = Blv
CurrentI = e/R = Blv/R
Opposing forceF = BIl = B²l²v/R
Mechanical powerP_mech = Fv = B²l²v²/R
Electrical powerP_elec = I²R = B²l²v²/R
ConclusionP_mech = P_elec

8. Conducting Loop Problems

For loop problems, first decide whether flux is increasing, decreasing or constant. Then choose the induced current direction that opposes that change.

Conducting loop cases in magnetic field
Entering fieldflux increasesinduced current opposes increaseFully insideflux constantno induced currentLeaving fieldflux decreasesinduced current supports field Direction is decided by whether flux through the loop is increasing, decreasing or constant.
Loop enters magnetic field: flux increases.
Loop leaves magnetic field: flux decreases.
Loop moves fully inside uniform field: flux constant, no current.
Expanding loop: area increases.
Contracting loop: area decreases.
Nearby loop current change: mutual induction occurs.

9. Solenoid and Moving Magnet Problems

When a magnet enters or leaves a solenoid, the flux linked with the solenoid changes. Faster motion gives greater rate of flux change and larger galvanometer deflection.

Moving magnet and solenoid
NS G Moving faster gives larger deflection. Stationary magnet gives no deflection.

10. NCERT-Style Conceptual Questions

NCERT-1Why does Lenz Law obey conservation of energy?

Difficulty: Conceptual

Answer: Because induced current always opposes the change producing it. External work is required, and this work is converted into electrical energy and heat.
Reasoning / Solution:

Because induced current always opposes the change producing it. External work is required, and this work is converted into electrical energy and heat.

NCERT-2Does induced current oppose magnetic field or change in flux?

Difficulty: Conceptual

Answer: It opposes the change in flux, not the field itself.
Reasoning / Solution:

It opposes the change in flux, not the field itself.

NCERT-3What happens if a magnet is kept stationary near a coil?

Difficulty: Conceptual

Answer: Flux remains constant, so induced EMF and induced current are zero.
Reasoning / Solution:

Flux remains constant, so induced EMF and induced current are zero.

NCERT-4Why does moving a magnet faster produce more current?

Difficulty: Conceptual

Answer: The rate of change of flux is larger, so induced EMF is larger.
Reasoning / Solution:

The rate of change of flux is larger, so induced EMF is larger.

NCERT-5Why is the negative sign present in Faraday's law?

Difficulty: Conceptual

Answer: It represents Lenz's law: induced EMF acts to oppose change in flux linkage.
Reasoning / Solution:

It represents Lenz's law: induced EMF acts to oppose change in flux linkage.

NCERT-6When a north pole approaches a coil, what is the near face?

Difficulty: Conceptual

Answer: The near face becomes north to oppose the approaching north pole.
Reasoning / Solution:

The near face becomes north to oppose the approaching north pole.

NCERT-7When a north pole moves away, what is the near face?

Difficulty: Conceptual

Answer: The near face becomes south to attract the receding north pole.
Reasoning / Solution:

The near face becomes south to attract the receding north pole.

NCERT-8Can induced EMF exist without induced current?

Difficulty: Conceptual

Answer: Yes, in an open circuit the EMF can exist but current cannot flow.
Reasoning / Solution:

Yes, in an open circuit the EMF can exist but current cannot flow.

NCERT-9Why does a loop fully inside uniform B have no induced current?

Difficulty: Conceptual

Answer: The flux linked with it is constant when area, field and orientation remain unchanged.
Reasoning / Solution:

The flux linked with it is constant when area, field and orientation remain unchanged.

NCERT-10How is Fleming's right hand rule different from Lenz law?

Difficulty: Conceptual

Answer: Fleming's rule gives direction in conductor motion cases; Lenz law explains the opposition principle.
Reasoning / Solution:

Fleming's rule gives direction in conductor motion cases; Lenz law explains the opposition principle.

11. Numerical Problems

NUM-1A rod of length 0.5 m moves at 4 m/s in a 0.2 T field perpendicular to the rod and velocity. Find induced EMF.

Difficulty: Numerical

Answer: 0.4 V
Reasoning / Solution:

Use e = Blv = 0.2×0.5×4 = 0.4 V.

NUM-2A rod of length 1 m moves at 3 m/s in B = 0.5 T with circuit resistance 2 Ω. Find current.

Difficulty: Numerical

Answer: 0.75 A
Reasoning / Solution:

e = Blv = 1.5 V, I = e/R = 1.5/2 = 0.75 A.

NUM-3For B = 0.4 T, l = 0.5 m, v = 2 m/s and R = 1 Ω, find opposing force on rod.

Difficulty: Numerical

Answer: 0.08 N
Reasoning / Solution:

I = Blv/R = 0.4 A, F = BIl = 0.4×0.4×0.5 = 0.08 N.

NUM-4A coil of 100 turns has flux change per turn 0.02 Wb in 0.5 s. Find average EMF.

Difficulty: Numerical

Answer: 4 V
Reasoning / Solution:

e = NΔΦ/Δt = 100×0.02/0.5 = 4 V.

NUM-5A loop resistance 5 Ω has flux change 0.1 Wb. Find total charge passed.

Difficulty: Numerical

Answer: 0.02 C
Reasoning / Solution:

q = ΔΦ/R = 0.1/5 = 0.02 C.

NUM-6A rod produces e = 6 V in a 3 Ω circuit. Find electrical power.

Difficulty: Numerical

Answer: 12 W
Reasoning / Solution:

P = e²/R = 36/3 = 12 W.

NUM-7If induced current is 2 A through 4 Ω, find heat produced in 5 s.

Difficulty: Numerical

Answer: 80 J
Reasoning / Solution:

H = I²Rt = 4×4×5 = 80 J.

NUM-8A magnetic flux decreases from 0.5 Wb to 0.1 Wb in 0.2 s through one loop. Find average EMF magnitude.

Difficulty: Numerical

Answer: 2 V
Reasoning / Solution:

e = |ΔΦ|/Δt = 0.4/0.2 = 2 V.

NUM-9A 50-turn coil has dΦ/dt = 0.03 Wb/s per turn. Find EMF.

Difficulty: Numerical

Answer: 1.5 V
Reasoning / Solution:

e = N dΦ/dt = 50×0.03 = 1.5 V.

NUM-10A rod moving in rails has mechanical power 20 W and circuit resistance 5 Ω. Find induced current.

Difficulty: Numerical

Answer: 2 A
Reasoning / Solution:

P = I²R, I = sqrt(20/5) = 2 A.

12. NEET Questions

Open each question card to view the correct answer and reasoning.

NEET-1According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

NEET-2If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

NEET-3When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

NEET-4Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

NEET-5Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

NEET-6The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

NEET-7If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

NEET-8A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

NEET-9Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

NEET-10If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

NEET-11According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

NEET-12If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

NEET-13When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

NEET-14Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

NEET-15Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

NEET-16The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

NEET-17If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

NEET-18A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

NEET-19Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

NEET-20If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

NEET-21According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

NEET-22If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

NEET-23When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

NEET-24Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

NEET-25Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

NEET-26The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

NEET-27If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

NEET-28A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

NEET-29Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

NEET-30If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

NEET-31According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

NEET-32If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

NEET-33When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

NEET-34Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

NEET-35Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

NEET-36The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

NEET-37If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

NEET-38A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

NEET-39Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

NEET-40If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

NEET-41According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

NEET-42If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

NEET-43When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

NEET-44Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

NEET-45Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

NEET-46The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

NEET-47If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

NEET-48A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

NEET-49Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

NEET-50If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

NEET-51According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

NEET-52If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

NEET-53When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

NEET-54Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

NEET-55Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

NEET-56The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

NEET-57If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

NEET-58A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

NEET-59Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

NEET-60If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

NEET-61According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

NEET-62If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

NEET-63When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

NEET-64Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

NEET-65Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

NEET-66The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

NEET-67If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

NEET-68A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

NEET-69Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

NEET-70If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

NEET-71According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

NEET-72If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

NEET-73When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

NEET-74Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

NEET-75Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

NEET-76The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

NEET-77If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

NEET-78A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

NEET-79Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

NEET-80If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

NEET-81According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

NEET-82If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

NEET-83When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

NEET-84Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

NEET-85Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

NEET-86The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

NEET-87If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

NEET-88A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

NEET-89Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

NEET-90If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

NEET-91According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

NEET-92If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

NEET-93When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

NEET-94Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

NEET-95Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

NEET-96The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

NEET-97If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

NEET-98A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

NEET-99Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

NEET-100If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

NEET-101According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

NEET-102If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

NEET-103When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

NEET-104Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

NEET-105Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

NEET-106The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

NEET-107If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

NEET-108A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

NEET-109Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

NEET-110If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

NEET-111According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

NEET-112If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: NEET Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

NEET-113When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

NEET-114Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: NEET Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

NEET-115Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: NEET Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

13. JEE Main Questions

Open each question card to view the correct answer and reasoning.

JEE-M-1According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-M-2If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-M-3When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-M-4Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-M-5Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-M-6The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-M-7If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-M-8A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-M-9Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-M-10If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-M-11According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-M-12If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-M-13When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-M-14Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-M-15Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-M-16The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-M-17If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-M-18A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-M-19Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-M-20If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-M-21According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-M-22If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-M-23When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-M-24Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-M-25Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-M-26The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-M-27If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-M-28A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-M-29Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-M-30If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-M-31According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-M-32If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-M-33When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-M-34Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-M-35Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-M-36The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-M-37If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-M-38A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-M-39Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-M-40If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-M-41According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-M-42If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-M-43When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-M-44Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-M-45Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-M-46The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-M-47If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-M-48A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-M-49Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-M-50If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-M-51According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-M-52If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-M-53When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-M-54Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-M-55Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-M-56The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-M-57If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-M-58A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-M-59Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-M-60If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-M-61According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-M-62If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-M-63When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-M-64Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-M-65Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-M-66The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-M-67If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-M-68A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-M-69Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-M-70If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-M-71According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-M-72If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Main Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-M-73When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-M-74Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Main Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-M-75Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Main Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

14. JEE Advanced Questions

Open each question card to view the correct answer and reasoning.

JEE-A-1According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-A-2If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-A-3When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-A-4Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-A-5Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-A-6The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-A-7If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-A-8A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-A-9Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-A-10If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-A-11According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-A-12If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-A-13When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-A-14Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-A-15Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-A-16The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-A-17If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-A-18A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-A-19Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-A-20If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-A-21According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-A-22If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-A-23When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-A-24Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-A-25Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-A-26The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-A-27If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-A-28A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-A-29Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-A-30If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-A-31According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-A-32If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-A-33When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-A-34Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-A-35Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-A-36The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-A-37If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-A-38A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-A-39Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-A-40If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-A-41According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-A-42If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-A-43When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-A-44Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-A-45Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-A-46The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-A-47If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-A-48A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-A-49Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-A-50If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-A-51According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-A-52If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-A-53When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-A-54Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-A-55Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-A-56The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-A-57If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-A-58A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-A-59Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-A-60If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-A-61According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-A-62If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-A-63When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-A-64Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-A-65Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-A-66The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-A-67If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-A-68A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-A-69Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-A-70If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-A-71According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-A-72If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-A-73When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-A-74Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-A-75Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

JEE-A-76The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

JEE-A-77If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

JEE-A-78A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

JEE-A-79Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

JEE-A-80If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

JEE-A-81According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

JEE-A-82If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: JEE Advanced Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

JEE-A-83When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

JEE-A-84Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: JEE Advanced Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

JEE-A-85Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: JEE Advanced Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

15. IB Physics

Open each question card to view the correct answer and reasoning.

IB-1According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: Structured

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

IB-2If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: Structured

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

IB-3When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: Structured

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

IB-4Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: Structured

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

IB-5Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: Structured

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

IB-6The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: Structured

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

IB-7If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: Structured

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

IB-8A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: Structured

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

IB-9Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: Structured

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

IB-10If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: Structured

Answer: B
Reasoning / Solution:

It would create energy from nothing.

IB-11According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: Structured

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

IB-12If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: Structured

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

IB-13When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: Structured

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

IB-14Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: Structured

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

IB-15Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: Structured

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

IB-16The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: Structured

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

IB-17If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: Structured

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

IB-18A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: Structured

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

IB-19Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: Structured

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

IB-20If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: Structured

Answer: B
Reasoning / Solution:

It would create energy from nothing.

16. ICSE / IGCSE Physics

Open each question card to view the correct answer and reasoning.

SCHOOL-1According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: School Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

SCHOOL-2If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: School Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

SCHOOL-3When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: School Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

SCHOOL-4Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: School Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

SCHOOL-5Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: School Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

SCHOOL-6The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: School Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

SCHOOL-7If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: School Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

SCHOOL-8A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: School Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

SCHOOL-9Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: School Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

SCHOOL-10If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: School Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

SCHOOL-11According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: School Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

SCHOOL-12If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: School Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

SCHOOL-13When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: School Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

SCHOOL-14Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: School Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

SCHOOL-15Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: School Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

SCHOOL-16The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: School Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

SCHOOL-17If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: School Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

SCHOOL-18A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: School Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

SCHOOL-19Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: School Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

SCHOOL-20If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: School Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

SCHOOL-21According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: School Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

SCHOOL-22If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: School Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

SCHOOL-23When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: School Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

SCHOOL-24Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: School Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

SCHOOL-25Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: School Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

SCHOOL-26The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: School Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

SCHOOL-27If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: School Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

SCHOOL-28A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: School Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

SCHOOL-29Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: School Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

SCHOOL-30If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: School Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

SCHOOL-31According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: School Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

SCHOOL-32If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: School Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

SCHOOL-33When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: School Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

SCHOOL-34Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: School Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

SCHOOL-35Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: School Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

SCHOOL-36The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: School Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

SCHOOL-37If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: School Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

SCHOOL-38A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: School Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

SCHOOL-39Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: School Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

SCHOOL-40If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: School Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

17. British Curriculum / A-Level Physics

Open each question card to view the correct answer and reasoning.

AL-1According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: A-Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

AL-2If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: A-Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

AL-3When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: A-Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

AL-4Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: A-Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

AL-5Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: A-Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

AL-6The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: A-Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

AL-7If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: A-Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

AL-8A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: A-Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

AL-9Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: A-Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

AL-10If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: A-Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

AL-11According to Lenz Law, induced current
  1. A) supports the cause
  2. B) opposes the change in flux
  3. C) always flows clockwise
  4. D) always flows anticlockwise

Difficulty: A-Level

Answer: B
Reasoning / Solution:

It opposes the change in magnetic flux that produces it.

AL-12If a north pole approaches a coil, the near face becomes
  1. A) north
  2. B) south
  3. C) neutral
  4. D) east

Difficulty: A-Level

Answer: A
Reasoning / Solution:

It opposes the approaching north pole by becoming north.

AL-13When flux through a loop is constant, induced current is
  1. A) maximum
  2. B) zero
  3. C) infinite
  4. D) negative

Difficulty: A-Level

Answer: B
Reasoning / Solution:

No flux change means no induced EMF.

AL-14Fleming's right hand rule is used for
  1. A) motor force
  2. B) generator current direction
  3. C) resistance
  4. D) capacitance

Difficulty: A-Level

Answer: B
Reasoning / Solution:

It gives direction of induced current in conductor-motion cases.

AL-15Mechanical power in ideal rod problem becomes
  1. A) chemical energy
  2. B) nuclear energy
  3. C) electrical power
  4. D) sound only

Difficulty: A-Level

Answer: C
Reasoning / Solution:

Pmech = Pelec in ideal EMI energy conversion.

AL-16The negative sign in e = −dΦ/dt represents
  1. A) wrong sign
  2. B) Lenz Law
  3. C) zero resistance
  4. D) open circuit

Difficulty: A-Level

Answer: B
Reasoning / Solution:

It indicates opposition to flux change.

AL-17If magnet speed near coil is doubled, induced EMF generally
  1. A) halves
  2. B) doubles
  3. C) becomes zero
  4. D) unchanged

Difficulty: A-Level

Answer: B
Reasoning / Solution:

Rate of flux change doubles.

AL-18A loop fully inside a uniform magnetic field moving with constant velocity has induced current
  1. A) zero
  2. B) large
  3. C) clockwise
  4. D) anticlockwise

Difficulty: A-Level

Answer: A
Reasoning / Solution:

Flux through the complete loop is unchanged.

AL-19Eddy currents oppose motion because of
  1. A) Ohm law only
  2. B) Coulomb law
  3. C) Lenz Law
  4. D) Kirchhoff law

Difficulty: A-Level

Answer: C
Reasoning / Solution:

Their magnetic effect opposes the change causing them.

AL-20If induced current supported the change, it would violate
  1. A) charge quantisation
  2. B) conservation of energy
  3. C) Snell law
  4. D) Newton's third law only

Difficulty: A-Level

Answer: B
Reasoning / Solution:

It would create energy from nothing.

18. Common Mistakes

Mistake 1

Thinking induced current supports the change.

Mistake 2

Confusing change of flux with flux itself.

Mistake 3

Choosing wrong clockwise or anticlockwise direction.

Mistake 4

Confusing Lenz Law with Fleming's Right Hand Rule.

Mistake 5

Forgetting the negative sign in Faraday's law.

Mistake 6

Forgetting that no flux change means no induced current.

Mistake 7

Wrong interpretation of induced coil polarity.

Mistake 8

Not applying conservation of energy.

Mistake 9

Using right hand rule without checking motion direction.

Mistake 10

Forgetting that open circuit can have induced EMF.

Mistake 11

Ignoring resistance while finding current.

Mistake 12

Using Blv when geometry is not perpendicular.

Mistake 13

Forgetting magnetic force opposes rod motion.

Mistake 14

Assuming eddy currents are always useful.

Mistake 15

Forgetting induced current needs a closed path.

Mistake 16

Ignoring flux due to nearby current change.

Mistake 17

Not drawing coil face polarity.

Mistake 18

Confusing field into page and out of page.

Mistake 19

Wrong sign in loop entering/leaving field.

Mistake 20

Using memorised direction without reasoning.

19. Final Revision Sheet

Lenz LawInduced current opposes flux change
Faraday-Lenz Lawe = −dΦ/dt
N-turn coile = −N dΦ/dt
Motional EMFe = Blv
CurrentI = Blv/R
ForceF = BIl
Energy resultP_mech = P_elec
No flux changee = 0
Four correct Lenz Law magnet-coil cases
1. North pole approaches N G Coil face near magnet: North Opposes approaching north pole. 2. North pole moves away N G Coil face near magnet: South Attracts receding north pole. 3. South pole approaches S G Coil face near magnet: South Opposes approaching south pole. 4. South pole moves away S G Coil face near magnet: North Attracts receding south pole.

Need Personal Help?

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