Magnetic Flux And Faraday's Law
Learn magnetic flux, flux linkage, Faraday's First Law, Faraday's Second Law and induced EMF with diagrams, formulas, solved numericals and exam-oriented practice.magnetic flux and faradays law
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1. Introduction to Magnetic Flux
Magnetic flux is the measure of magnetic field passing through a surface. It depends on magnetic field strength, area of the surface and orientation of the surface. The area vector is perpendicular to the surface, so the angle θ is always measured between magnetic field B and area vector A.
Φ = B · AΦ = BA cosθθ = 0°, Φ = BAθ = 90°, Φ = 02. Unit and Dimension of Magnetic Flux
From Φ = BA, magnetic flux unit is tesla metre squared. This unit is called weber.
1 Wb = 1 T m²T = N A⁻¹ m⁻¹[Φ] = [B][A] = M L² T⁻² A⁻¹3. Flux Through Surface
Flux is maximum when magnetic field is parallel to area vector. Flux is zero when magnetic field is perpendicular to area vector, which means the field lies in the plane of the surface.
4. Ways to Change Flux
Induced EMF occurs only when magnetic flux changes. Since Φ = BA cosθ, flux can change by changing B, changing A, or changing orientation θ.
5. Flux Linkage
If a coil has N turns and flux through each turn is Φ, the total flux linkage is NΦ. More turns means larger induced EMF for the same flux change.
NΦe = −d(NΦ)/dte = −N dΦ/dt6. Faraday's First Law
Whenever magnetic flux linked with a circuit changes, an EMF is induced in the circuit. If the circuit is closed, induced current flows. If the circuit is open, induced EMF can exist but current does not flow.
7. Faraday's Second Law
The magnitude of induced EMF is equal to the rate of change of flux linkage. The negative sign represents Lenz's law.
e = − d(NΦ)/dte = −N dΦ/dte_avg = NΔΦ/ΔtStep 1
Find initial flux Φ₁ = BA cosθ.
Step 2
Find final flux Φ₂ after the change.
Step 3
Use ΔΦ = Φ₂ − Φ₁ and multiply by N.
Step 4
Divide by time interval to get average induced EMF.
8. Lenz's Law and Conservation of Energy
Lenz's law states that the induced current flows in such a direction that it opposes the change in magnetic flux which produced it. This is why EMI follows conservation of energy and does not create free energy.
9. Conservation of Energy in EMI
When a magnet approaches a coil, the induced current creates a magnetic field opposing the approach. External mechanical work is required. This work becomes electrical energy and heat in the circuit. In motional EMF problems, mechanical power supplied is converted into electrical power.
P_mech = P_elecP = I²R = e²/Rq = NΔΦ/R10. Numerical Questions From Uploaded Images
All visible EMI numerical questions from the uploaded book-page images are solved below and the printed answers are independently verified.
Q1Coil removed from magnetic field
Question: A magnetic field of flux density 1.0 Wb m⁻² acts normal to a 80 turn coil of 0.01 m² area. Find the e.m.f. induced in it, if this coil is removed from the field in 0.1 second.
Given Data: B = 1.0 T, N = 80, A = 0.01 m², Δt = 0.1 s.
e = NΔΦ/Δt = NBA/ΔtInitially, flux linkage = NBA because the field is normal to the coil.
When removed from the field, final flux is zero.
e = 80 × 1.0 × 0.01 / 0.1 = 8 V.
Q2Magnetic field changes uniformly
Question: Find the magnitude of e.m.f. induced in a 200 turns coil with cross sectional area 0.16 m², if the magnetic field through the coil changes from 0.10 Wb m⁻² to 0.30 Wb m⁻² at a uniform rate over a period of 0.05 s.
Given Data: N = 200, A = 0.16 m², ΔB = 0.20 T, Δt = 0.05 s.
e = NAΔB/Δte = 200 × 0.16 × 0.20 / 0.05.
e = 6.4 / 0.05 = 128 V.
Q3Field perpendicular to coil plane
Question: Find the e.m.f. induced in a coil of 200 turns and cross sectional area 0.2 m², when a magnetic field perpendicular to the plane of the coil changes from 0.1 Wb m⁻² to 0.5 Wb m⁻² at a uniform rate over a period of 0.05 s.
Given Data: N = 200, A = 0.2 m², ΔB = 0.4 T, Δt = 0.05 s.
e = NAΔB/ΔtSince B is perpendicular to the plane, the area vector is parallel to B, so cosθ = 1.
e = 200 × 0.2 × 0.4 / 0.05 = 320 V.
Q4Square coil rotated through 180 degrees
Question: A square copper coil of each side 8 cm consists of 100 turns. The coil is initially in vertical plane, such that the plane of the coil is normal to uniform magnetic field of induction 0.4 Wb m⁻². The coil is turned through 180° about a horizontal axis in 0.2 s. Find the induced e.m.f.
Given Data: N = 100, side = 8 cm = 0.08 m, A = 0.0064 m², B = 0.4 T, Δt = 0.2 s.
e = N(2BA)/ΔtInitial flux per turn = +BA. After rotation through 180°, flux per turn = −BA.
Change in flux per turn = 2BA.
e = 100 × 2 × 0.4 × 0.0064 / 0.2 = 2.56 V.
Q5Rotating metal disc
Question: A metal disc of radius 200 cm is rotated at a constant angular speed of 60 rad s⁻¹ in a plane at right angles to an external field of magnetic induction 0.05 Wb m⁻². Find the e.m.f. induced between the centre and a point on the rim.
Given Data: R = 200 cm = 2 m, ω = 60 rad s⁻¹, B = 0.05 T.
e = (1/2)BωR²The motional EMF between centre and rim of a rotating disc is e = 1/2 BωR².
e = 1/2 × 0.05 × 60 × 2² = 6 V.
Q6Time required to reduce field to zero
Question: A uniform magnetic flux density of 0.1 Wb m⁻² extends over a plane circuit of area 2 m² and is normal to it. How quickly must the field be reduced to zero, if an e.m.f. of 100 volt is to be induced in the circuit ?
Given Data: B = 0.1 T, A = 2 m², e = 100 V.
e = AΔB/ΔtΔΦ = AΔB = 2 × 0.1 = 0.2 Wb.
Δt = ΔΦ/e = 0.2/100 = 0.002 s.
Q7Circular loop changed into square
Question: A wire 88 cm long bent into a circular loop is placed perpendicular to the magnetic field of flux density 2.5 Wb m⁻². Within 0.5 sec, the loop is changed into a square of each side 22 cm and flux density is increased to 3.0 Wb m⁻². Calculate the value of e.m.f. induced.
Given Data: Wire length = 0.88 m, initial B = 2.5 T, final square side = 0.22 m, final B = 3.0 T, Δt = 0.5 s.
e = |ΔΦ|/Δt, Φ = BAInitial circle radius r = L/(2π) = 0.88/(2π) = 0.14 m.
Initial area = πr² = 0.0616 m².
Initial flux = 2.5 × 0.0616 = 0.154 Wb.
Final square area = (0.22)² = 0.0484 m².
Final flux = 3.0 × 0.0484 = 0.1452 Wb.
|ΔΦ| = |0.1452 − 0.154| = 0.0088 Wb.
e = 0.0088/0.5 = 0.0176 V ≈ 0.018 V.
Q8Coil turned through 180 degrees
Question: A coil of mean area of 500 cm² and having 1000 turns is held perpendicular to a uniform field of 0.4 G. The coil is turned through 180° in 1/10 sec. Calculate the average induced e.m.f.
Given Data: A = 500 cm² = 0.05 m², N = 1000, B = 0.4 G = 4 × 10⁻⁵ T, Δt = 0.1 s.
e = N(2BA)/ΔtRotation through 180° reverses the flux, so change in flux per turn is 2BA.
e = 1000 × 2 × 4×10⁻⁵ × 0.05 / 0.1.
e = 0.04 V.
Q9Coil inserted in magnetic field
Question: The area of a coil of 25 turns is 1.6 cm². This coil is inserted in 0.3 sec in a magnetic field of 1.8 Wb/m² such that its plane is perpendicular to the flux lines of the field. Calculate the e.m.f. induced in the coil. Also, calculate the total charge that passes through the wire, if its resistance is 10 Ω.
Given Data: N = 25, A = 1.6 cm² = 1.6×10⁻⁴ m², B = 1.8 T, Δt = 0.3 s, R = 10 Ω.
e = NBA/Δt, q = NΔΦ/RInitial flux is zero and final flux per turn is BA.
e = 25 × 1.8 × 1.6×10⁻⁴ / 0.3 = 2.4×10⁻² V.
Total charge q = NΔΦ/R = 25×1.8×1.6×10⁻⁴ / 10 = 7.2×10⁻⁴ C.
Q10Coil removed from strong magnetic field
Question: A magnetic field of flux density 10 T acts normal to a coil of 50 turns having 100 cm² area. Find e.m.f. induced if the coil is removed from magnetic field in 0.1 second ?
Given Data: B = 10 T, N = 50, A = 100 cm² = 0.01 m², Δt = 0.1 s.
e = NBA/ΔtRemoving the coil reduces flux from BA to zero.
e = 50 × 10 × 0.01 / 0.1 = 50 V.
Q11Induced current in square copper frame
Question: A uniform magnetic field B exists in a direction perpendicular to the plane of a square frame made of copper wire. The wire has a diameter of 2 mm and a total length of 40 cm. The magnetic field changes with time at a steady rate dB/dt = 0.02 T/s. Find the current induced in the frame. Resistivity of copper = 1.7 × 10⁻⁸ ohm-m.
Given Data: Total length = 0.40 m, square side = 0.10 m, loop area = 0.01 m², wire diameter = 2 mm, ρ = 1.7×10⁻⁸ Ωm, dB/dt = 0.02 T/s.
e = A(dB/dt), R = ρL/a, I = e/RArea of square loop = (0.10)² = 0.01 m².
Induced EMF = A(dB/dt) = 0.01×0.02 = 2×10⁻⁴ V.
Wire cross-section a = π(1×10⁻³)² = π×10⁻⁶ m².
Resistance R = ρL/a = 1.7×10⁻⁸×0.40/(π×10⁻⁶) = 2.16×10⁻³ Ω.
I = e/R = 2×10⁻⁴/(2.16×10⁻³) = 9.3×10⁻² A.
11. NEET Numerical and Concept MCQs
Practice questions are arranged in toggle format. Open each card to see answer and explanation.
NEET-1Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-2A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-3The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-4For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-5Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-6If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-7A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-8Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-9The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-10If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-11Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-12A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-13The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-14For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-15Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-16If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-17A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-18Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-19The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-20If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-21Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-22A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-23The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-24For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-25Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-26If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-27A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-28Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-29The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-30If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-31Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-32A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-33The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-34For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-35Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-36If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-37A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-38Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-39The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-40If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-41Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-42A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-43The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-44For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-45Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-46If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-47A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-48Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-49The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-50If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-51Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-52A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-53The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-54For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-55Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-56If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-57A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-58Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-59The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-60If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-61Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-62A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-63The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-64For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-65Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-66If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-67A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-68Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-69The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-70If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-71Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-72A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-73The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-74For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-75Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-76If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-77A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-78Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-79The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-80If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-81Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-82A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-83The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-84For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-85Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-86If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-87A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-88Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-89The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-90If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-91Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-92A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-93The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-94For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-95Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-96If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-97A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-98Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-99The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-100If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-101Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-102A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-103The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-104For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-105Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-106If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-107A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-108Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-109The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-110If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-111Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-112A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-113The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-114For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-115Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-116If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-117A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-118Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-119The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-120If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-121Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-122A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-123The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-124For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-125Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-126If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-127A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-128Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-129The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-130If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-131Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-132A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-133The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-134For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-135Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-136If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-137A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-138Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-139The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-140If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-141Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-142A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-143The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-144For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-145Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-146If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-147A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-148Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-149The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-150If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-151Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-152A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-153The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-154For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-155Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-156If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-157A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-158Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-159The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-160If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
NEET-161Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: NEET Level
EMF is proportional to change in flux divided by time.
NEET-162A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: NEET Level
No change in flux means no induced EMF.
NEET-163The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: NEET Level
Magnetic flux is measured in weber.
NEET-164For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: NEET Level
Area vector is perpendicular to the surface.
NEET-165Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: NEET Level
The sign shows induced EMF opposes flux change.
NEET-166If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: NEET Level
Flux linkage is NΦ.
NEET-167A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: NEET Level
Area inside field decreases.
NEET-168Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: NEET Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
NEET-169The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: NEET Level
∫εdt = −Δ(NΦ).
NEET-170If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: NEET Level
Area vector is perpendicular to B, so θ = 90°.
12. JEE Main Practice
Practice questions are arranged in toggle format. Open each card to see answer and explanation.
JEE-M-1Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-2A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-3The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-4For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-5Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
JEE-M-6If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Main Level
Flux linkage is NΦ.
JEE-M-7A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Main Level
Area inside field decreases.
JEE-M-8Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Main Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-M-9The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Main Level
∫εdt = −Δ(NΦ).
JEE-M-10If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Main Level
Area vector is perpendicular to B, so θ = 90°.
JEE-M-11Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-12A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-13The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-14For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-15Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
JEE-M-16If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Main Level
Flux linkage is NΦ.
JEE-M-17A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Main Level
Area inside field decreases.
JEE-M-18Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Main Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-M-19The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Main Level
∫εdt = −Δ(NΦ).
JEE-M-20If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Main Level
Area vector is perpendicular to B, so θ = 90°.
JEE-M-21Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-22A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-23The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-24For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-25Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
JEE-M-26If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Main Level
Flux linkage is NΦ.
JEE-M-27A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Main Level
Area inside field decreases.
JEE-M-28Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Main Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-M-29The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Main Level
∫εdt = −Δ(NΦ).
JEE-M-30If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Main Level
Area vector is perpendicular to B, so θ = 90°.
JEE-M-31Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-32A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-33The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-34For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-35Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
JEE-M-36If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Main Level
Flux linkage is NΦ.
JEE-M-37A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Main Level
Area inside field decreases.
JEE-M-38Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Main Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-M-39The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Main Level
∫εdt = −Δ(NΦ).
JEE-M-40If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Main Level
Area vector is perpendicular to B, so θ = 90°.
JEE-M-41Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-42A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-43The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-44For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-45Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
JEE-M-46If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Main Level
Flux linkage is NΦ.
JEE-M-47A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Main Level
Area inside field decreases.
JEE-M-48Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Main Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-M-49The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Main Level
∫εdt = −Δ(NΦ).
JEE-M-50If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Main Level
Area vector is perpendicular to B, so θ = 90°.
JEE-M-51Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-52A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-53The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-54For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-55Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
JEE-M-56If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Main Level
Flux linkage is NΦ.
JEE-M-57A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Main Level
Area inside field decreases.
JEE-M-58Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Main Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-M-59The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Main Level
∫εdt = −Δ(NΦ).
JEE-M-60If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Main Level
Area vector is perpendicular to B, so θ = 90°.
JEE-M-61Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-62A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-63The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-64For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-65Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
JEE-M-66If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Main Level
Flux linkage is NΦ.
JEE-M-67A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Main Level
Area inside field decreases.
JEE-M-68Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Main Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-M-69The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Main Level
∫εdt = −Δ(NΦ).
JEE-M-70If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Main Level
Area vector is perpendicular to B, so θ = 90°.
JEE-M-71Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-72A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-73The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-74For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-75Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
JEE-M-76If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Main Level
Flux linkage is NΦ.
JEE-M-77A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Main Level
Area inside field decreases.
JEE-M-78Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Main Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-M-79The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Main Level
∫εdt = −Δ(NΦ).
JEE-M-80If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Main Level
Area vector is perpendicular to B, so θ = 90°.
JEE-M-81Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-82A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-83The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-84For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-85Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
JEE-M-86If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Main Level
Flux linkage is NΦ.
JEE-M-87A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Main Level
Area inside field decreases.
JEE-M-88Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Main Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-M-89The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Main Level
∫εdt = −Δ(NΦ).
JEE-M-90If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Main Level
Area vector is perpendicular to B, so θ = 90°.
JEE-M-91Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-92A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-93The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-94For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-95Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
JEE-M-96If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Main Level
Flux linkage is NΦ.
JEE-M-97A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Main Level
Area inside field decreases.
JEE-M-98Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Main Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-M-99The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Main Level
∫εdt = −Δ(NΦ).
JEE-M-100If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Main Level
Area vector is perpendicular to B, so θ = 90°.
JEE-M-101Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-102A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-103The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-104For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-105Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
JEE-M-106If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Main Level
Flux linkage is NΦ.
JEE-M-107A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Main Level
Area inside field decreases.
JEE-M-108Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Main Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-M-109The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Main Level
∫εdt = −Δ(NΦ).
JEE-M-110If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Main Level
Area vector is perpendicular to B, so θ = 90°.
JEE-M-111Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-112A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-113The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-114For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-115Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
JEE-M-116If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Main Level
Flux linkage is NΦ.
JEE-M-117A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Main Level
Area inside field decreases.
JEE-M-118Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Main Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-M-119The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Main Level
∫εdt = −Δ(NΦ).
JEE-M-120If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Main Level
Area vector is perpendicular to B, so θ = 90°.
JEE-M-121Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-122A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-123The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-124For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-125Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
JEE-M-126If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Main Level
Flux linkage is NΦ.
JEE-M-127A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Main Level
Area inside field decreases.
JEE-M-128Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Main Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-M-129The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Main Level
∫εdt = −Δ(NΦ).
JEE-M-130If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Main Level
Area vector is perpendicular to B, so θ = 90°.
JEE-M-131Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-132A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-133The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-134For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-135Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
JEE-M-136If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Main Level
Flux linkage is NΦ.
JEE-M-137A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Main Level
Area inside field decreases.
JEE-M-138Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Main Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-M-139The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Main Level
∫εdt = −Δ(NΦ).
JEE-M-140If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Main Level
Area vector is perpendicular to B, so θ = 90°.
JEE-M-141Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Main Level
EMF is proportional to change in flux divided by time.
JEE-M-142A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Main Level
No change in flux means no induced EMF.
JEE-M-143The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Main Level
Magnetic flux is measured in weber.
JEE-M-144For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Main Level
Area vector is perpendicular to the surface.
JEE-M-145Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Main Level
The sign shows induced EMF opposes flux change.
13. JEE Advanced Practice
Practice questions are arranged in toggle format. Open each card to see answer and explanation.
JEE-A-1Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Advanced Level
EMF is proportional to change in flux divided by time.
JEE-A-2A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Advanced Level
No change in flux means no induced EMF.
JEE-A-3The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Advanced Level
Magnetic flux is measured in weber.
JEE-A-4For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Advanced Level
Area vector is perpendicular to the surface.
JEE-A-5Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Advanced Level
The sign shows induced EMF opposes flux change.
JEE-A-6If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Advanced Level
Flux linkage is NΦ.
JEE-A-7A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Advanced Level
Area inside field decreases.
JEE-A-8Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Advanced Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-A-9The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Advanced Level
∫εdt = −Δ(NΦ).
JEE-A-10If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Advanced Level
Area vector is perpendicular to B, so θ = 90°.
JEE-A-11Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Advanced Level
EMF is proportional to change in flux divided by time.
JEE-A-12A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Advanced Level
No change in flux means no induced EMF.
JEE-A-13The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Advanced Level
Magnetic flux is measured in weber.
JEE-A-14For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Advanced Level
Area vector is perpendicular to the surface.
JEE-A-15Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Advanced Level
The sign shows induced EMF opposes flux change.
JEE-A-16If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Advanced Level
Flux linkage is NΦ.
JEE-A-17A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Advanced Level
Area inside field decreases.
JEE-A-18Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Advanced Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-A-19The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Advanced Level
∫εdt = −Δ(NΦ).
JEE-A-20If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Advanced Level
Area vector is perpendicular to B, so θ = 90°.
JEE-A-21Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Advanced Level
EMF is proportional to change in flux divided by time.
JEE-A-22A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Advanced Level
No change in flux means no induced EMF.
JEE-A-23The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Advanced Level
Magnetic flux is measured in weber.
JEE-A-24For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Advanced Level
Area vector is perpendicular to the surface.
JEE-A-25Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Advanced Level
The sign shows induced EMF opposes flux change.
JEE-A-26If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Advanced Level
Flux linkage is NΦ.
JEE-A-27A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Advanced Level
Area inside field decreases.
JEE-A-28Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Advanced Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-A-29The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Advanced Level
∫εdt = −Δ(NΦ).
JEE-A-30If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Advanced Level
Area vector is perpendicular to B, so θ = 90°.
JEE-A-31Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Advanced Level
EMF is proportional to change in flux divided by time.
JEE-A-32A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Advanced Level
No change in flux means no induced EMF.
JEE-A-33The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Advanced Level
Magnetic flux is measured in weber.
JEE-A-34For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Advanced Level
Area vector is perpendicular to the surface.
JEE-A-35Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Advanced Level
The sign shows induced EMF opposes flux change.
JEE-A-36If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Advanced Level
Flux linkage is NΦ.
JEE-A-37A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Advanced Level
Area inside field decreases.
JEE-A-38Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Advanced Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-A-39The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Advanced Level
∫εdt = −Δ(NΦ).
JEE-A-40If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Advanced Level
Area vector is perpendicular to B, so θ = 90°.
JEE-A-41Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Advanced Level
EMF is proportional to change in flux divided by time.
JEE-A-42A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Advanced Level
No change in flux means no induced EMF.
JEE-A-43The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Advanced Level
Magnetic flux is measured in weber.
JEE-A-44For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Advanced Level
Area vector is perpendicular to the surface.
JEE-A-45Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Advanced Level
The sign shows induced EMF opposes flux change.
JEE-A-46If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Advanced Level
Flux linkage is NΦ.
JEE-A-47A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Advanced Level
Area inside field decreases.
JEE-A-48Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Advanced Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-A-49The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Advanced Level
∫εdt = −Δ(NΦ).
JEE-A-50If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Advanced Level
Area vector is perpendicular to B, so θ = 90°.
JEE-A-51Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Advanced Level
EMF is proportional to change in flux divided by time.
JEE-A-52A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Advanced Level
No change in flux means no induced EMF.
JEE-A-53The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Advanced Level
Magnetic flux is measured in weber.
JEE-A-54For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Advanced Level
Area vector is perpendicular to the surface.
JEE-A-55Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Advanced Level
The sign shows induced EMF opposes flux change.
JEE-A-56If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Advanced Level
Flux linkage is NΦ.
JEE-A-57A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Advanced Level
Area inside field decreases.
JEE-A-58Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Advanced Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-A-59The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Advanced Level
∫εdt = −Δ(NΦ).
JEE-A-60If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Advanced Level
Area vector is perpendicular to B, so θ = 90°.
JEE-A-61Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Advanced Level
EMF is proportional to change in flux divided by time.
JEE-A-62A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Advanced Level
No change in flux means no induced EMF.
JEE-A-63The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Advanced Level
Magnetic flux is measured in weber.
JEE-A-64For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Advanced Level
Area vector is perpendicular to the surface.
JEE-A-65Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Advanced Level
The sign shows induced EMF opposes flux change.
JEE-A-66If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Advanced Level
Flux linkage is NΦ.
JEE-A-67A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Advanced Level
Area inside field decreases.
JEE-A-68Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Advanced Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-A-69The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Advanced Level
∫εdt = −Δ(NΦ).
JEE-A-70If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Advanced Level
Area vector is perpendicular to B, so θ = 90°.
JEE-A-71Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Advanced Level
EMF is proportional to change in flux divided by time.
JEE-A-72A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Advanced Level
No change in flux means no induced EMF.
JEE-A-73The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Advanced Level
Magnetic flux is measured in weber.
JEE-A-74For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Advanced Level
Area vector is perpendicular to the surface.
JEE-A-75Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Advanced Level
The sign shows induced EMF opposes flux change.
JEE-A-76If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: JEE Advanced Level
Flux linkage is NΦ.
JEE-A-77A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: JEE Advanced Level
Area inside field decreases.
JEE-A-78Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: JEE Advanced Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
JEE-A-79The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: JEE Advanced Level
∫εdt = −Δ(NΦ).
JEE-A-80If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: JEE Advanced Level
Area vector is perpendicular to B, so θ = 90°.
JEE-A-81Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: JEE Advanced Level
EMF is proportional to change in flux divided by time.
JEE-A-82A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: JEE Advanced Level
No change in flux means no induced EMF.
JEE-A-83The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: JEE Advanced Level
Magnetic flux is measured in weber.
JEE-A-84For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: JEE Advanced Level
Area vector is perpendicular to the surface.
JEE-A-85Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: JEE Advanced Level
The sign shows induced EMF opposes flux change.
14. IB Physics Structured Questions
Practice questions are arranged in toggle format. Open each card to see answer and explanation.
IB-1Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: Structured
EMF is proportional to change in flux divided by time.
IB-2A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: Structured
No change in flux means no induced EMF.
IB-3The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: Structured
Magnetic flux is measured in weber.
IB-4For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: Structured
Area vector is perpendicular to the surface.
IB-5Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: Structured
The sign shows induced EMF opposes flux change.
IB-6If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: Structured
Flux linkage is NΦ.
IB-7A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: Structured
Area inside field decreases.
IB-8Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: Structured
For ε = Blv, rod, velocity and field must be mutually perpendicular.
IB-9The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: Structured
∫εdt = −Δ(NΦ).
IB-10If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: Structured
Area vector is perpendicular to B, so θ = 90°.
IB-11Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: Structured
EMF is proportional to change in flux divided by time.
IB-12A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: Structured
No change in flux means no induced EMF.
IB-13The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: Structured
Magnetic flux is measured in weber.
IB-14For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: Structured
Area vector is perpendicular to the surface.
IB-15Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: Structured
The sign shows induced EMF opposes flux change.
IB-16If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: Structured
Flux linkage is NΦ.
IB-17A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: Structured
Area inside field decreases.
IB-18Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: Structured
For ε = Blv, rod, velocity and field must be mutually perpendicular.
IB-19The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: Structured
∫εdt = −Δ(NΦ).
IB-20If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: Structured
Area vector is perpendicular to B, so θ = 90°.
15. IGCSE / ICSE Practice
Practice questions are arranged in toggle format. Open each card to see answer and explanation.
SCHOOL-1Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: School Level
EMF is proportional to change in flux divided by time.
SCHOOL-2A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: School Level
No change in flux means no induced EMF.
SCHOOL-3The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: School Level
Magnetic flux is measured in weber.
SCHOOL-4For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: School Level
Area vector is perpendicular to the surface.
SCHOOL-5Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: School Level
The sign shows induced EMF opposes flux change.
SCHOOL-6If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: School Level
Flux linkage is NΦ.
SCHOOL-7A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: School Level
Area inside field decreases.
SCHOOL-8Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: School Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
SCHOOL-9The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: School Level
∫εdt = −Δ(NΦ).
SCHOOL-10If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: School Level
Area vector is perpendicular to B, so θ = 90°.
SCHOOL-11Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: School Level
EMF is proportional to change in flux divided by time.
SCHOOL-12A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: School Level
No change in flux means no induced EMF.
SCHOOL-13The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: School Level
Magnetic flux is measured in weber.
SCHOOL-14For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: School Level
Area vector is perpendicular to the surface.
SCHOOL-15Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: School Level
The sign shows induced EMF opposes flux change.
SCHOOL-16If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: School Level
Flux linkage is NΦ.
SCHOOL-17A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: School Level
Area inside field decreases.
SCHOOL-18Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: School Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
SCHOOL-19The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: School Level
∫εdt = −Δ(NΦ).
SCHOOL-20If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: School Level
Area vector is perpendicular to B, so θ = 90°.
SCHOOL-21Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: School Level
EMF is proportional to change in flux divided by time.
SCHOOL-22A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: School Level
No change in flux means no induced EMF.
SCHOOL-23The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: School Level
Magnetic flux is measured in weber.
SCHOOL-24For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: School Level
Area vector is perpendicular to the surface.
SCHOOL-25Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: School Level
The sign shows induced EMF opposes flux change.
SCHOOL-26If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: School Level
Flux linkage is NΦ.
SCHOOL-27A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: School Level
Area inside field decreases.
SCHOOL-28Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: School Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
SCHOOL-29The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: School Level
∫εdt = −Δ(NΦ).
SCHOOL-30If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: School Level
Area vector is perpendicular to B, so θ = 90°.
SCHOOL-31Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: School Level
EMF is proportional to change in flux divided by time.
SCHOOL-32A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: School Level
No change in flux means no induced EMF.
SCHOOL-33The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: School Level
Magnetic flux is measured in weber.
SCHOOL-34For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: School Level
Area vector is perpendicular to the surface.
SCHOOL-35Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: School Level
The sign shows induced EMF opposes flux change.
SCHOOL-36If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: School Level
Flux linkage is NΦ.
SCHOOL-37A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: School Level
Area inside field decreases.
SCHOOL-38Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: School Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
SCHOOL-39The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: School Level
∫εdt = −Δ(NΦ).
SCHOOL-40If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: School Level
Area vector is perpendicular to B, so θ = 90°.
16. British Curriculum / A-Level Practice
Practice questions are arranged in toggle format. Open each card to see answer and explanation.
AL-1Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: A-Level
EMF is proportional to change in flux divided by time.
AL-2A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: A-Level
No change in flux means no induced EMF.
AL-3The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: A-Level
Magnetic flux is measured in weber.
AL-4For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: A-Level
Area vector is perpendicular to the surface.
AL-5Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: A-Level
The sign shows induced EMF opposes flux change.
AL-6If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: A-Level
Flux linkage is NΦ.
AL-7A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: A-Level
Area inside field decreases.
AL-8Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: A-Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
AL-9The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: A-Level
∫εdt = −Δ(NΦ).
AL-10If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: A-Level
Area vector is perpendicular to B, so θ = 90°.
AL-11Flux in a coil is doubled in half the time. Average induced EMF becomes
- A) same
- B) double
- C) four times
- D) half
Difficulty: A-Level
EMF is proportional to change in flux divided by time.
AL-12A loop is stationary in a steady uniform magnetic field. Induced EMF is
- A) maximum
- B) zero
- C) BA/t
- D) NBI
Difficulty: A-Level
No change in flux means no induced EMF.
AL-13The SI unit of magnetic flux is
- A) tesla
- B) weber
- C) henry
- D) volt
Difficulty: A-Level
Magnetic flux is measured in weber.
AL-14For Φ = BA cosθ, θ is angle between
- A) B and plane
- B) B and area vector
- C) current and field
- D) area and current
Difficulty: A-Level
Area vector is perpendicular to the surface.
AL-15Negative sign in Faraday's law represents
- A) negative voltage only
- B) Lenz's law
- C) zero flux
- D) resistance
Difficulty: A-Level
The sign shows induced EMF opposes flux change.
AL-16If N is increased, induced EMF
- A) decreases
- B) becomes zero
- C) increases proportionally
- D) is independent
Difficulty: A-Level
Flux linkage is NΦ.
AL-17A conducting loop is pulled out of a magnetic field. Flux
- A) increases
- B) decreases
- C) stays constant
- D) becomes infinite
Difficulty: A-Level
Area inside field decreases.
AL-18Motional EMF in a straight rod is maximum when v is
- A) parallel to B
- B) parallel to rod
- C) perpendicular to B and rod
- D) zero
Difficulty: A-Level
For ε = Blv, rod, velocity and field must be mutually perpendicular.
AL-19The area under an EMF-time graph gives
- A) magnetic field
- B) change in flux linkage
- C) resistance
- D) current
Difficulty: A-Level
∫εdt = −Δ(NΦ).
AL-20If the plane of a coil is parallel to magnetic field lines, flux is
- A) BA
- B) zero
- C) 2BA
- D) B/A
Difficulty: A-Level
Area vector is perpendicular to B, so θ = 90°.
17. Common Student Mistakes
Mistake 1
Confusing magnetic field B with magnetic flux Φ.
Mistake 2
Using Φ = BA without checking angle.
Mistake 3
Using angle with the plane instead of area vector.
Mistake 4
Forgetting flux linkage NΦ.
Mistake 5
Missing the negative sign in Faraday's law.
Mistake 6
Treating Lenz's law as optional.
Mistake 7
Wrong induced current direction.
Mistake 8
Ignoring whether the circuit is open or closed.
Mistake 9
Forgetting unit conversion from cm² to m².
Mistake 10
Forgetting gauss to tesla conversion.
Mistake 11
Using final flux only instead of change in flux.
Mistake 12
Forgetting factor 2 when coil rotates through 180°.
Mistake 13
Using ε = Blv for a rotating disc instead of ε = 1/2BωR².
Mistake 14
Not distinguishing average EMF and instantaneous EMF.
Mistake 15
Forgetting that total charge q = NΔΦ/R.
Mistake 16
Using resistance incorrectly in current calculation.
Mistake 17
Ignoring wire cross-sectional area in frame resistance.
Mistake 18
Taking flux zero when the plane is normal to field.
Mistake 19
Drawing area vector parallel to surface.
Mistake 20
Not writing units in final answer.
18. Revision Sheet
Φ = BA cosθNΦe = −d(NΦ)/dte = NΔΦ/Δte = Blve = 1/2 BωR²q = NΔΦ/RR = ρL/A_wireNeed Personal Help?
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