Production • Ozone Layer • Germicidal Lamps • LASIK Surgery • Hazards and Uses
Ultraviolet Rays Complete coaching-style notes on Ultraviolet Rays for CBSE, NEET, JEE Main, JEE Advanced, IB Physics, IGCSE Physics, ICSE Physics and A-Level Physics with wavelength ranges, production methods, ozone layer protection, germicidal applications, LASIK surgery, hazards, PYQs, MCQs, numericals and case studies.
Section 1: Introduction to Ultraviolet Rays Ultraviolet rays are electromagnetic waves with wavelengths shorter than visible violet light and longer than X-rays. They occupy the region just beyond the violet end of the visible spectrum. UV radiation was discovered through its strong chemical action beyond the violet part of the spectrum. UV rays have higher frequency and higher photon energy than visible light, so they can produce fluorescence, photoelectric emission, chemical changes and biological effects.
Infrared → Visible → Ultraviolet → X-rays UV: shorter wavelength, higher energy than visible violet
Section 2: Wavelength and Frequency Range Type Wavelength Range Frequency Range Energy Range Penetrating Power Biological Effects UV-A 315-400 nm 7.5×10^14-9.5×10^14 Hz 3.1-3.9 eV Highest among UV types reaching skin deeply Skin aging, tanning, indirect DNA damage UV-B 280-315 nm 9.5×10^14-1.07×10^15 Hz 3.9-4.4 eV Moderate; partly absorbed by ozone Sunburn, vitamin D production, direct DNA damage UV-C 100-280 nm 1.07×10^15-3×10^15 Hz 4.4-12.4 eV Lowest at Earth surface due to ozone absorption Germicidal action, sterilization, severe biological damage
Section 3: Production of Ultraviolet Rays Electric arc method
Mercury vapor lamp
Hydrogen discharge tube
Synchrotron radiation
High temperature sources
Sun as source
Mercury vapor lamp UV radiation Section 4: Detection of UV Rays Photographic plates
Fluorescence
Photoelectric effect
UV detectors
Photodiodes
Spectrometers
Section 5: Ozone Layer The ozone layer is mainly located in the stratosphere. It protects life by absorbing a large fraction of harmful ultraviolet radiation. Oxygen molecules absorb high-energy UV and form oxygen atoms; these atoms combine with O₂ to form ozone. Ozone also absorbs UV and breaks back into oxygen, creating the ozone-oxygen cycle.
Importance
Ozone depletion
Troposphere Stratosphere: Ozone Layer Higher atmosphere O₃ absorbs UV-B and UV-C
Section 6: Germicidal Lamps Germicidal lamps use mainly UV-C radiation. UV-C damages DNA and RNA of bacteria, viruses and other microorganisms, stopping reproduction and causing sterilization. They are used in water purification, air purification, hospitals, laboratories and industrial disinfection. Direct exposure is dangerous, so shielding and safety protocols are essential.
Section 7: LASIK Surgery LASIK stands for Laser-Assisted In Situ Keratomileusis. It uses an excimer laser, often in the ultraviolet region, to remove microscopic layers of corneal tissue. This reshapes the cornea and corrects focusing errors. Advantages include high precision and quick recovery, while limitations include suitability requirements, dry eye risk and possible glare or halos.
Excimer UV laser Cornea reshaping Section 8: Applications of Ultraviolet Rays Sterilization
Water purification
Currency note detection
Forensic science
Astronomy
Security markings
Medical applications
LASIK surgery
Industrial applications
Section 9: Hazards of Ultraviolet Radiation Skin cancer
DNA damage
Eye damage
Cataract
Sunburn
Premature aging
Safety precautions: Use sunscreen, UV-blocking glasses, protective clothing, shielding around UV lamps and avoid direct UV-C exposure.
Section 10: Important Formulas Section 11: Conceptual Questions Conceptual Question 1. Why is UV called ultraviolet? Conceptual
Answer: It lies beyond violet in the electromagnetic spectrum, at shorter wavelength and higher frequency than visible violet light.
Conceptual Question 2. Why is UV more energetic than visible light? Conceptual
Answer: Photon energy E = hc/λ, and UV has shorter wavelength than visible light.
Conceptual Question 3. Why is UV-C germicidal? Conceptual
Answer: UV-C has enough photon energy to damage DNA and RNA of microorganisms, preventing reproduction.
Conceptual Question 4. Why does ozone protect life? Conceptual
Answer: Ozone absorbs most harmful UV-B and UV-C radiation before it reaches Earth surface.
Conceptual Question 5. What is ozone layer? Conceptual
Answer: It is a region in the stratosphere with relatively high ozone concentration.
Conceptual Question 6. Why can UV damage eyes? Conceptual
Answer: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
Conceptual Question 7. Why does UV cause sunburn? Conceptual
Answer: UV-B can damage skin cells and trigger inflammation, producing sunburn.
Conceptual Question 8. What is fluorescence? Conceptual
Answer: Fluorescence is emission of visible light by a substance after absorbing higher-energy radiation such as UV.
Conceptual Question 9. How are UV rays detected by photographic plates? Conceptual
Answer: UV radiation can cause chemical changes in photographic materials, darkening the plate.
Conceptual Question 10. Why are mercury vapor lamps used for UV? Conceptual
Answer: Excited mercury atoms emit strong ultraviolet spectral lines.
Conceptual Question 11. What is LASIK? Conceptual
Answer: LASIK is Laser-Assisted In Situ Keratomileusis, a surgery that reshapes the cornea to correct vision.
Conceptual Question 12. Why is an excimer laser used in LASIK? Conceptual
Answer: Excimer UV lasers remove corneal tissue very precisely with minimal thermal damage.
Conceptual Question 13. What are CFCs? Conceptual
Answer: Chlorofluorocarbons are chemicals that release chlorine in the stratosphere and destroy ozone.
Conceptual Question 14. What is ozone hole? Conceptual
Answer: It is a severe seasonal thinning of ozone concentration, especially over polar regions.
Conceptual Question 15. How does UV help forensic science? Conceptual
Answer: Many body fluids, fibres and security inks fluoresce under UV light.
Conceptual Question 16. How does UV help currency detection? Conceptual
Answer: Security markings on notes fluoresce under UV radiation.
Conceptual Question 17. Why is direct UV-C exposure dangerous? Conceptual
Answer: It can damage skin and eyes because it is strongly absorbed by biological molecules.
Conceptual Question 18. What is photoelectric detection of UV? Conceptual
Answer: UV photons eject electrons from suitable surfaces, producing a measurable current.
Conceptual Question 19. Why does UV sterilize water? Conceptual
Answer: UV-C damages genetic material of microorganisms in water.
Conceptual Question 20. Why is the Sun a source of UV? Conceptual
Answer: The hot solar photosphere and chromosphere emit radiation over a broad spectrum including UV.
Conceptual Question 21. What is the frequency range of UV? Conceptual
Answer: Approximately 7.5×10^14 Hz to 3×10^15 Hz.
Conceptual Question 22. What is the wavelength range of UV? Conceptual
Answer: Approximately 100 nm to 400 nm.
Conceptual Question 23. Why is UV invisible? Conceptual
Answer: Human photoreceptors do not respond to wavelengths shorter than visible violet.
Conceptual Question 24. What is UV-A associated with? Conceptual
Answer: UV-A is strongly associated with aging and tanning effects.
Conceptual Question 25. What is UV-B associated with? Conceptual
Answer: UV-B is associated with burning, sunburn and direct DNA damage.
Conceptual Question 26. What is UV-C associated with? Conceptual
Answer: UV-C is associated with cleaning, sterilization and germicidal action.
Conceptual Question 27. Why do hospitals use UV carefully? Conceptual
Answer: UV can sterilize surfaces but can also harm human skin and eyes.
Conceptual Question 28. Why is ozone depletion harmful? Conceptual
Answer: It allows more UV-B to reach Earth, increasing health and ecological risks.
Conceptual Question 29. What is synchrotron UV? Conceptual
Answer: High-speed charged particles in circular accelerators emit intense electromagnetic radiation including UV.
Conceptual Question 30. What is a UV spectrometer? Conceptual
Answer: An instrument used to measure intensity as a function of ultraviolet wavelength.
Conceptual Question 31. What is UV index? Conceptual
Answer: A measure of the strength of sunburn-producing ultraviolet radiation at a place and time.
Conceptual Question 32. Why use sunscreen? Conceptual
Answer: Sunscreen absorbs or reflects UV radiation and reduces skin damage.
Conceptual Question 33. Why does glass block some UV? Conceptual
Answer: Ordinary glass absorbs much of UV-B and UV-C but may transmit some UV-A.
Conceptual Question 34. How does UV support astronomy? Conceptual
Answer: UV observations reveal hot stars, active galaxies and high-energy regions.
Conceptual Question 35. Why is UV used in industry? Conceptual
Answer: It enables curing, inspection, sterilization and fluorescence-based testing.
Conceptual Question 36. What is ozone-oxygen cycle? Conceptual
Answer: Oxygen and ozone interconvert under UV radiation, absorbing harmful UV in the process.
Conceptual Question 37. Why does UV-B produce vitamin D? Conceptual
Answer: UV-B initiates chemical reactions in skin that lead to vitamin D production.
Conceptual Question 38. Why should UV lamps not be viewed directly? Conceptual
Answer: UV can injure cornea and lens even when brightness seems low.
Conceptual Question 39. Why does UV have high photon energy? Conceptual
Answer: Its frequency is high, and E = hν.
Conceptual Question 40. What is the order of UV types by wavelength? Conceptual
Answer: UV-C has shortest wavelength, UV-B is intermediate, and UV-A has longest wavelength.
Section 12: CBSE Board Questions Short answer 1. Why is UV called ultraviolet? CBSE
Detailed solution: It lies beyond violet in the electromagnetic spectrum, at shorter wavelength and higher frequency than visible violet light.
Long answer 2. Why is UV more energetic than visible light? CBSE
Detailed solution: Photon energy E = hc/λ, and UV has shorter wavelength than visible light.
Assertion Reason 3. Why is UV-C germicidal? CBSE
Detailed solution: UV-C has enough photon energy to damage DNA and RNA of microorganisms, preventing reproduction.
Case Study 4. Why does ozone protect life? CBSE
Detailed solution: Ozone absorbs most harmful UV-B and UV-C radiation before it reaches Earth surface.
Short answer 5. What is ozone layer? CBSE
Detailed solution: It is a region in the stratosphere with relatively high ozone concentration.
Long answer 6. Why can UV damage eyes? CBSE
Detailed solution: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
Assertion Reason 7. Why does UV cause sunburn? CBSE
Detailed solution: UV-B can damage skin cells and trigger inflammation, producing sunburn.
Case Study 8. What is fluorescence? CBSE
Detailed solution: Fluorescence is emission of visible light by a substance after absorbing higher-energy radiation such as UV.
Short answer 9. How are UV rays detected by photographic plates? CBSE
Detailed solution: UV radiation can cause chemical changes in photographic materials, darkening the plate.
Long answer 10. Why are mercury vapor lamps used for UV? CBSE
Detailed solution: Excited mercury atoms emit strong ultraviolet spectral lines.
Assertion Reason 11. What is LASIK? CBSE
Detailed solution: LASIK is Laser-Assisted In Situ Keratomileusis, a surgery that reshapes the cornea to correct vision.
Case Study 12. Why is an excimer laser used in LASIK? CBSE
Detailed solution: Excimer UV lasers remove corneal tissue very precisely with minimal thermal damage.
Short answer 13. What are CFCs? CBSE
Detailed solution: Chlorofluorocarbons are chemicals that release chlorine in the stratosphere and destroy ozone.
Long answer 14. What is ozone hole? CBSE
Detailed solution: It is a severe seasonal thinning of ozone concentration, especially over polar regions.
Assertion Reason 15. How does UV help forensic science? CBSE
Detailed solution: Many body fluids, fibres and security inks fluoresce under UV light.
Case Study 16. How does UV help currency detection? CBSE
Detailed solution: Security markings on notes fluoresce under UV radiation.
Short answer 17. Why is direct UV-C exposure dangerous? CBSE
Detailed solution: It can damage skin and eyes because it is strongly absorbed by biological molecules.
Long answer 18. What is photoelectric detection of UV? CBSE
Detailed solution: UV photons eject electrons from suitable surfaces, producing a measurable current.
Assertion Reason 19. Why does UV sterilize water? CBSE
Detailed solution: UV-C damages genetic material of microorganisms in water.
Case Study 20. Why is the Sun a source of UV? CBSE
Detailed solution: The hot solar photosphere and chromosphere emit radiation over a broad spectrum including UV.
Section 13: NEET PYQs Style Questions NEET MCQ 1. UV radiation lies beyond which visible colour? NEET
Options: A. Red B. Green C. Violet D. Yellow
Answer: Violet
Explanation: Ultraviolet means beyond violet.
NEET MCQ 2. Most germicidal UV is mainly: NEET
Options: A. UV-A B. UV-B C. UV-C D. Infrared
Answer: UV-C
Explanation: UV-C damages microbial DNA effectively.
NEET MCQ 3. Ozone layer is mainly located in: NEET
Options: A. troposphere B. stratosphere C. mesosphere D. ionosphere
Answer: stratosphere
Explanation: Most atmospheric ozone is in the stratosphere.
NEET MCQ 4. UV photon energy is given by: NEET
Options: A. E = hν B. E = h/ν C. E = λ/h D. E = c/h
Answer: E = hν
Explanation: Planck relation.
NEET MCQ 5. UV wavelength is roughly: NEET
Options: A. 100-400 nm B. 400-700 nm C. 1-10 m D. 10-100 km
Answer: 100-400 nm
Explanation: This is the approximate UV band.
NEET MCQ 6. UV-A is commonly linked with: NEET
Options: A. aging B. cleaning only C. radio D. X-rays
Answer: aging
Explanation: Memory trick: UV-A → Aging.
NEET MCQ 7. UV-B is commonly linked with: NEET
Options: A. burning B. Bluetooth C. broadcasting D. gamma decay
Answer: burning
Explanation: Memory trick: UV-B → Burning.
NEET MCQ 8. UV-C is commonly linked with: NEET
Options: A. cleaning B. visible green C. microwaves D. sound
Answer: cleaning
Explanation: Memory trick: UV-C → Cleaning.
NEET MCQ 9. LASIK commonly uses: NEET
Options: A. excimer laser B. radio antenna C. magnetron D. klystron
Answer: excimer laser
Explanation: Excimer UV lasers reshape cornea precisely.
NEET MCQ 10. CFCs damage ozone by releasing: NEET
Options: A. chlorine radicals B. oxygen only C. helium D. iron
Answer: chlorine radicals
Explanation: Chlorine participates in ozone-destroying reactions.
NEET MCQ 11. UV radiation lies beyond which visible colour? NEET
Options: A. Red B. Green C. Violet D. Yellow
Answer: Violet
Explanation: Ultraviolet means beyond violet.
NEET MCQ 12. Most germicidal UV is mainly: NEET
Options: A. UV-A B. UV-B C. UV-C D. Infrared
Answer: UV-C
Explanation: UV-C damages microbial DNA effectively.
NEET MCQ 13. Ozone layer is mainly located in: NEET
Options: A. troposphere B. stratosphere C. mesosphere D. ionosphere
Answer: stratosphere
Explanation: Most atmospheric ozone is in the stratosphere.
NEET MCQ 14. UV photon energy is given by: NEET
Options: A. E = hν B. E = h/ν C. E = λ/h D. E = c/h
Answer: E = hν
Explanation: Planck relation.
NEET MCQ 15. UV wavelength is roughly: NEET
Options: A. 100-400 nm B. 400-700 nm C. 1-10 m D. 10-100 km
Answer: 100-400 nm
Explanation: This is the approximate UV band.
NEET MCQ 16. UV-A is commonly linked with: NEET
Options: A. aging B. cleaning only C. radio D. X-rays
Answer: aging
Explanation: Memory trick: UV-A → Aging.
NEET MCQ 17. UV-B is commonly linked with: NEET
Options: A. burning B. Bluetooth C. broadcasting D. gamma decay
Answer: burning
Explanation: Memory trick: UV-B → Burning.
NEET MCQ 18. UV-C is commonly linked with: NEET
Options: A. cleaning B. visible green C. microwaves D. sound
Answer: cleaning
Explanation: Memory trick: UV-C → Cleaning.
NEET MCQ 19. LASIK commonly uses: NEET
Options: A. excimer laser B. radio antenna C. magnetron D. klystron
Answer: excimer laser
Explanation: Excimer UV lasers reshape cornea precisely.
NEET MCQ 20. CFCs damage ozone by releasing: NEET
Options: A. chlorine radicals B. oxygen only C. helium D. iron
Answer: chlorine radicals
Explanation: Chlorine participates in ozone-destroying reactions.
NEET MCQ 21. UV radiation lies beyond which visible colour? NEET
Options: A. Red B. Green C. Violet D. Yellow
Answer: Violet
Explanation: Ultraviolet means beyond violet.
NEET MCQ 22. Most germicidal UV is mainly: NEET
Options: A. UV-A B. UV-B C. UV-C D. Infrared
Answer: UV-C
Explanation: UV-C damages microbial DNA effectively.
NEET MCQ 23. Ozone layer is mainly located in: NEET
Options: A. troposphere B. stratosphere C. mesosphere D. ionosphere
Answer: stratosphere
Explanation: Most atmospheric ozone is in the stratosphere.
NEET MCQ 24. UV photon energy is given by: NEET
Options: A. E = hν B. E = h/ν C. E = λ/h D. E = c/h
Answer: E = hν
Explanation: Planck relation.
NEET MCQ 25. UV wavelength is roughly: NEET
Options: A. 100-400 nm B. 400-700 nm C. 1-10 m D. 10-100 km
Answer: 100-400 nm
Explanation: This is the approximate UV band.
NEET MCQ 26. UV-A is commonly linked with: NEET
Options: A. aging B. cleaning only C. radio D. X-rays
Answer: aging
Explanation: Memory trick: UV-A → Aging.
NEET MCQ 27. UV-B is commonly linked with: NEET
Options: A. burning B. Bluetooth C. broadcasting D. gamma decay
Answer: burning
Explanation: Memory trick: UV-B → Burning.
NEET MCQ 28. UV-C is commonly linked with: NEET
Options: A. cleaning B. visible green C. microwaves D. sound
Answer: cleaning
Explanation: Memory trick: UV-C → Cleaning.
NEET MCQ 29. LASIK commonly uses: NEET
Options: A. excimer laser B. radio antenna C. magnetron D. klystron
Answer: excimer laser
Explanation: Excimer UV lasers reshape cornea precisely.
NEET MCQ 30. CFCs damage ozone by releasing: NEET
Options: A. chlorine radicals B. oxygen only C. helium D. iron
Answer: chlorine radicals
Explanation: Chlorine participates in ozone-destroying reactions.
NEET MCQ 31. UV radiation lies beyond which visible colour? NEET
Options: A. Red B. Green C. Violet D. Yellow
Answer: Violet
Explanation: Ultraviolet means beyond violet.
NEET MCQ 32. Most germicidal UV is mainly: NEET
Options: A. UV-A B. UV-B C. UV-C D. Infrared
Answer: UV-C
Explanation: UV-C damages microbial DNA effectively.
NEET MCQ 33. Ozone layer is mainly located in: NEET
Options: A. troposphere B. stratosphere C. mesosphere D. ionosphere
Answer: stratosphere
Explanation: Most atmospheric ozone is in the stratosphere.
NEET MCQ 34. UV photon energy is given by: NEET
Options: A. E = hν B. E = h/ν C. E = λ/h D. E = c/h
Answer: E = hν
Explanation: Planck relation.
NEET MCQ 35. UV wavelength is roughly: NEET
Options: A. 100-400 nm B. 400-700 nm C. 1-10 m D. 10-100 km
Answer: 100-400 nm
Explanation: This is the approximate UV band.
NEET MCQ 36. UV-A is commonly linked with: NEET
Options: A. aging B. cleaning only C. radio D. X-rays
Answer: aging
Explanation: Memory trick: UV-A → Aging.
NEET MCQ 37. UV-B is commonly linked with: NEET
Options: A. burning B. Bluetooth C. broadcasting D. gamma decay
Answer: burning
Explanation: Memory trick: UV-B → Burning.
NEET MCQ 38. UV-C is commonly linked with: NEET
Options: A. cleaning B. visible green C. microwaves D. sound
Answer: cleaning
Explanation: Memory trick: UV-C → Cleaning.
NEET MCQ 39. LASIK commonly uses: NEET
Options: A. excimer laser B. radio antenna C. magnetron D. klystron
Answer: excimer laser
Explanation: Excimer UV lasers reshape cornea precisely.
NEET MCQ 40. CFCs damage ozone by releasing: NEET
Options: A. chlorine radicals B. oxygen only C. helium D. iron
Answer: chlorine radicals
Explanation: Chlorine participates in ozone-destroying reactions.
Section 14: JEE Main Questions JEE Main Numerical 1. Find frequency of UV of wavelength 100 nm. JEE Main
λ = 100 nm = 100×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (100×10⁻⁹) Hz. Answer: 3.00e+15 Hz JEE Main Concept 2. Why is UV more energetic than visible light? JEE Main
Solution: Photon energy E = hc/λ, and UV has shorter wavelength than visible light.
JEE Main Numerical 3. Find frequency of UV of wavelength 120 nm. JEE Main
λ = 120 nm = 120×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (120×10⁻⁹) Hz. Answer: 2.50e+15 Hz JEE Main Concept 4. Why does ozone protect life? JEE Main
Solution: Ozone absorbs most harmful UV-B and UV-C radiation before it reaches Earth surface.
JEE Main Numerical 5. Find frequency of UV of wavelength 140 nm. JEE Main
λ = 140 nm = 140×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (140×10⁻⁹) Hz. Answer: 2.14e+15 Hz JEE Main Concept 6. Why can UV damage eyes? JEE Main
Solution: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
JEE Main Numerical 7. Find frequency of UV of wavelength 160 nm. JEE Main
λ = 160 nm = 160×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (160×10⁻⁹) Hz. Answer: 1.88e+15 Hz JEE Main Concept 8. What is fluorescence? JEE Main
Solution: Fluorescence is emission of visible light by a substance after absorbing higher-energy radiation such as UV.
JEE Main Numerical 9. Find frequency of UV of wavelength 180 nm. JEE Main
λ = 180 nm = 180×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (180×10⁻⁹) Hz. Answer: 1.67e+15 Hz JEE Main Concept 10. Why are mercury vapor lamps used for UV? JEE Main
Solution: Excited mercury atoms emit strong ultraviolet spectral lines.
JEE Main Numerical 11. Find frequency of UV of wavelength 200 nm. JEE Main
λ = 200 nm = 200×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (200×10⁻⁹) Hz. Answer: 1.50e+15 Hz JEE Main Concept 12. Why is an excimer laser used in LASIK? JEE Main
Solution: Excimer UV lasers remove corneal tissue very precisely with minimal thermal damage.
JEE Main Numerical 13. Find frequency of UV of wavelength 220 nm. JEE Main
λ = 220 nm = 220×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (220×10⁻⁹) Hz. Answer: 1.36e+15 Hz JEE Main Concept 14. What is ozone hole? JEE Main
Solution: It is a severe seasonal thinning of ozone concentration, especially over polar regions.
JEE Main Numerical 15. Find frequency of UV of wavelength 240 nm. JEE Main
λ = 240 nm = 240×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (240×10⁻⁹) Hz. Answer: 1.25e+15 Hz JEE Main Concept 16. How does UV help currency detection? JEE Main
Solution: Security markings on notes fluoresce under UV radiation.
JEE Main Numerical 17. Find frequency of UV of wavelength 260 nm. JEE Main
λ = 260 nm = 260×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (260×10⁻⁹) Hz. Answer: 1.15e+15 Hz JEE Main Concept 18. What is photoelectric detection of UV? JEE Main
Solution: UV photons eject electrons from suitable surfaces, producing a measurable current.
JEE Main Numerical 19. Find frequency of UV of wavelength 280 nm. JEE Main
λ = 280 nm = 280×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (280×10⁻⁹) Hz. Answer: 1.07e+15 Hz JEE Main Concept 20. Why is the Sun a source of UV? JEE Main
Solution: The hot solar photosphere and chromosphere emit radiation over a broad spectrum including UV.
JEE Main Numerical 21. Find frequency of UV of wavelength 300 nm. JEE Main
λ = 300 nm = 300×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (300×10⁻⁹) Hz. Answer: 1.00e+15 Hz JEE Main Concept 22. What is the wavelength range of UV? JEE Main
Solution: Approximately 100 nm to 400 nm.
JEE Main Numerical 23. Find frequency of UV of wavelength 320 nm. JEE Main
λ = 320 nm = 320×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (320×10⁻⁹) Hz. Answer: 9.38e+14 Hz JEE Main Concept 24. What is UV-A associated with? JEE Main
Solution: UV-A is strongly associated with aging and tanning effects.
JEE Main Numerical 25. Find frequency of UV of wavelength 340 nm. JEE Main
λ = 340 nm = 340×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (340×10⁻⁹) Hz. Answer: 8.82e+14 Hz JEE Main Concept 26. What is UV-C associated with? JEE Main
Solution: UV-C is associated with cleaning, sterilization and germicidal action.
JEE Main Numerical 27. Find frequency of UV of wavelength 360 nm. JEE Main
λ = 360 nm = 360×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (360×10⁻⁹) Hz. Answer: 8.33e+14 Hz JEE Main Concept 28. Why is ozone depletion harmful? JEE Main
Solution: It allows more UV-B to reach Earth, increasing health and ecological risks.
JEE Main Numerical 29. Find frequency of UV of wavelength 380 nm. JEE Main
λ = 380 nm = 380×10⁻⁹ m. Use ν = c/λ. ν = 3×10⁸ / (380×10⁻⁹) Hz. Answer: 7.89e+14 Hz JEE Main Concept 30. What is a UV spectrometer? JEE Main
Solution: An instrument used to measure intensity as a function of ultraviolet wavelength.
Section 15: JEE Advanced Questions JEE Advanced Question 1. What is fluorescence? JEE Advanced
Answer: Fluorescence is emission of visible light by a substance after absorbing higher-energy radiation such as UV.
JEE Advanced Question 2. How are UV rays detected by photographic plates? JEE Advanced
Answer: UV radiation can cause chemical changes in photographic materials, darkening the plate.
JEE Advanced Question 3. Why are mercury vapor lamps used for UV? JEE Advanced
Answer: Excited mercury atoms emit strong ultraviolet spectral lines.
JEE Advanced Question 4. What is LASIK? JEE Advanced
Answer: LASIK is Laser-Assisted In Situ Keratomileusis, a surgery that reshapes the cornea to correct vision.
JEE Advanced Question 5. Why is an excimer laser used in LASIK? JEE Advanced
Answer: Excimer UV lasers remove corneal tissue very precisely with minimal thermal damage.
JEE Advanced Question 6. What are CFCs? JEE Advanced
Answer: Chlorofluorocarbons are chemicals that release chlorine in the stratosphere and destroy ozone.
JEE Advanced Question 7. What is ozone hole? JEE Advanced
Answer: It is a severe seasonal thinning of ozone concentration, especially over polar regions.
JEE Advanced Question 8. How does UV help forensic science? JEE Advanced
Answer: Many body fluids, fibres and security inks fluoresce under UV light.
JEE Advanced Question 9. How does UV help currency detection? JEE Advanced
Answer: Security markings on notes fluoresce under UV radiation.
JEE Advanced Question 10. Why is direct UV-C exposure dangerous? JEE Advanced
Answer: It can damage skin and eyes because it is strongly absorbed by biological molecules.
JEE Advanced Question 11. What is photoelectric detection of UV? JEE Advanced
Answer: UV photons eject electrons from suitable surfaces, producing a measurable current.
JEE Advanced Question 12. Why does UV sterilize water? JEE Advanced
Answer: UV-C damages genetic material of microorganisms in water.
JEE Advanced Question 13. Why is the Sun a source of UV? JEE Advanced
Answer: The hot solar photosphere and chromosphere emit radiation over a broad spectrum including UV.
JEE Advanced Question 14. What is the frequency range of UV? JEE Advanced
Answer: Approximately 7.5×10^14 Hz to 3×10^15 Hz.
JEE Advanced Question 15. What is the wavelength range of UV? JEE Advanced
Answer: Approximately 100 nm to 400 nm.
JEE Advanced Question 16. Why is UV invisible? JEE Advanced
Answer: Human photoreceptors do not respond to wavelengths shorter than visible violet.
JEE Advanced Question 17. What is UV-A associated with? JEE Advanced
Answer: UV-A is strongly associated with aging and tanning effects.
JEE Advanced Question 18. What is UV-B associated with? JEE Advanced
Answer: UV-B is associated with burning, sunburn and direct DNA damage.
JEE Advanced Question 19. What is UV-C associated with? JEE Advanced
Answer: UV-C is associated with cleaning, sterilization and germicidal action.
JEE Advanced Question 20. Why do hospitals use UV carefully? JEE Advanced
Answer: UV can sterilize surfaces but can also harm human skin and eyes.
Section 16: IB Physics Questions IB Physics Question 1. What is fluorescence? IB Physics
Answer: Fluorescence is emission of visible light by a substance after absorbing higher-energy radiation such as UV.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 2. How are UV rays detected by photographic plates? IB Physics
Answer: UV radiation can cause chemical changes in photographic materials, darkening the plate.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 3. Why are mercury vapor lamps used for UV? IB Physics
Answer: Excited mercury atoms emit strong ultraviolet spectral lines.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 4. What is LASIK? IB Physics
Answer: LASIK is Laser-Assisted In Situ Keratomileusis, a surgery that reshapes the cornea to correct vision.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 5. Why is an excimer laser used in LASIK? IB Physics
Answer: Excimer UV lasers remove corneal tissue very precisely with minimal thermal damage.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 6. What are CFCs? IB Physics
Answer: Chlorofluorocarbons are chemicals that release chlorine in the stratosphere and destroy ozone.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 7. What is ozone hole? IB Physics
Answer: It is a severe seasonal thinning of ozone concentration, especially over polar regions.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 8. How does UV help forensic science? IB Physics
Answer: Many body fluids, fibres and security inks fluoresce under UV light.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 9. How does UV help currency detection? IB Physics
Answer: Security markings on notes fluoresce under UV radiation.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 10. Why is direct UV-C exposure dangerous? IB Physics
Answer: It can damage skin and eyes because it is strongly absorbed by biological molecules.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 11. What is photoelectric detection of UV? IB Physics
Answer: UV photons eject electrons from suitable surfaces, producing a measurable current.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 12. Why does UV sterilize water? IB Physics
Answer: UV-C damages genetic material of microorganisms in water.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 13. Why is the Sun a source of UV? IB Physics
Answer: The hot solar photosphere and chromosphere emit radiation over a broad spectrum including UV.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 14. What is the frequency range of UV? IB Physics
Answer: Approximately 7.5×10^14 Hz to 3×10^15 Hz.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 15. What is the wavelength range of UV? IB Physics
Answer: Approximately 100 nm to 400 nm.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 16. Why is UV invisible? IB Physics
Answer: Human photoreceptors do not respond to wavelengths shorter than visible violet.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 17. What is UV-A associated with? IB Physics
Answer: UV-A is strongly associated with aging and tanning effects.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
IB Physics Question 18. What is UV-B associated with? IB Physics
Answer: UV-B is associated with burning, sunburn and direct DNA damage.
Marking scheme: 1 mark for correct fact, 1 mark for explanation, 1 mark for correct formula/application.
Section 17: IGCSE Questions IGCSE Question 1. What is fluorescence? IGCSE
Answer: Fluorescence is emission of visible light by a substance after absorbing higher-energy radiation such as UV.
IGCSE Question 2. How are UV rays detected by photographic plates? IGCSE
Answer: UV radiation can cause chemical changes in photographic materials, darkening the plate.
IGCSE Question 3. Why are mercury vapor lamps used for UV? IGCSE
Answer: Excited mercury atoms emit strong ultraviolet spectral lines.
IGCSE Question 4. What is LASIK? IGCSE
Answer: LASIK is Laser-Assisted In Situ Keratomileusis, a surgery that reshapes the cornea to correct vision.
IGCSE Question 5. Why is an excimer laser used in LASIK? IGCSE
Answer: Excimer UV lasers remove corneal tissue very precisely with minimal thermal damage.
IGCSE Question 6. What are CFCs? IGCSE
Answer: Chlorofluorocarbons are chemicals that release chlorine in the stratosphere and destroy ozone.
IGCSE Question 7. What is ozone hole? IGCSE
Answer: It is a severe seasonal thinning of ozone concentration, especially over polar regions.
IGCSE Question 8. How does UV help forensic science? IGCSE
Answer: Many body fluids, fibres and security inks fluoresce under UV light.
IGCSE Question 9. How does UV help currency detection? IGCSE
Answer: Security markings on notes fluoresce under UV radiation.
IGCSE Question 10. Why is direct UV-C exposure dangerous? IGCSE
Answer: It can damage skin and eyes because it is strongly absorbed by biological molecules.
IGCSE Question 11. What is photoelectric detection of UV? IGCSE
Answer: UV photons eject electrons from suitable surfaces, producing a measurable current.
IGCSE Question 12. Why does UV sterilize water? IGCSE
Answer: UV-C damages genetic material of microorganisms in water.
IGCSE Question 13. Why is the Sun a source of UV? IGCSE
Answer: The hot solar photosphere and chromosphere emit radiation over a broad spectrum including UV.
IGCSE Question 14. What is the frequency range of UV? IGCSE
Answer: Approximately 7.5×10^14 Hz to 3×10^15 Hz.
IGCSE Question 15. What is the wavelength range of UV? IGCSE
Answer: Approximately 100 nm to 400 nm.
IGCSE Question 16. Why is UV invisible? IGCSE
Answer: Human photoreceptors do not respond to wavelengths shorter than visible violet.
IGCSE Question 17. What is UV-A associated with? IGCSE
Answer: UV-A is strongly associated with aging and tanning effects.
IGCSE Question 18. What is UV-B associated with? IGCSE
Answer: UV-B is associated with burning, sunburn and direct DNA damage.
Section 18: ICSE Questions ICSE Question 1. What is fluorescence? ICSE
Answer: Fluorescence is emission of visible light by a substance after absorbing higher-energy radiation such as UV.
ICSE Question 2. How are UV rays detected by photographic plates? ICSE
Answer: UV radiation can cause chemical changes in photographic materials, darkening the plate.
ICSE Question 3. Why are mercury vapor lamps used for UV? ICSE
Answer: Excited mercury atoms emit strong ultraviolet spectral lines.
ICSE Question 4. What is LASIK? ICSE
Answer: LASIK is Laser-Assisted In Situ Keratomileusis, a surgery that reshapes the cornea to correct vision.
ICSE Question 5. Why is an excimer laser used in LASIK? ICSE
Answer: Excimer UV lasers remove corneal tissue very precisely with minimal thermal damage.
ICSE Question 6. What are CFCs? ICSE
Answer: Chlorofluorocarbons are chemicals that release chlorine in the stratosphere and destroy ozone.
ICSE Question 7. What is ozone hole? ICSE
Answer: It is a severe seasonal thinning of ozone concentration, especially over polar regions.
ICSE Question 8. How does UV help forensic science? ICSE
Answer: Many body fluids, fibres and security inks fluoresce under UV light.
ICSE Question 9. How does UV help currency detection? ICSE
Answer: Security markings on notes fluoresce under UV radiation.
ICSE Question 10. Why is direct UV-C exposure dangerous? ICSE
Answer: It can damage skin and eyes because it is strongly absorbed by biological molecules.
ICSE Question 11. What is photoelectric detection of UV? ICSE
Answer: UV photons eject electrons from suitable surfaces, producing a measurable current.
ICSE Question 12. Why does UV sterilize water? ICSE
Answer: UV-C damages genetic material of microorganisms in water.
ICSE Question 13. Why is the Sun a source of UV? ICSE
Answer: The hot solar photosphere and chromosphere emit radiation over a broad spectrum including UV.
ICSE Question 14. What is the frequency range of UV? ICSE
Answer: Approximately 7.5×10^14 Hz to 3×10^15 Hz.
ICSE Question 15. What is the wavelength range of UV? ICSE
Answer: Approximately 100 nm to 400 nm.
ICSE Question 16. Why is UV invisible? ICSE
Answer: Human photoreceptors do not respond to wavelengths shorter than visible violet.
ICSE Question 17. What is UV-A associated with? ICSE
Answer: UV-A is strongly associated with aging and tanning effects.
ICSE Question 18. What is UV-B associated with? ICSE
Answer: UV-B is associated with burning, sunburn and direct DNA damage.
Section 19: A-Level Physics Questions A-Level Question 1. What is fluorescence? A-Level
Answer: Fluorescence is emission of visible light by a substance after absorbing higher-energy radiation such as UV.
A-Level Question 2. How are UV rays detected by photographic plates? A-Level
Answer: UV radiation can cause chemical changes in photographic materials, darkening the plate.
A-Level Question 3. Why are mercury vapor lamps used for UV? A-Level
Answer: Excited mercury atoms emit strong ultraviolet spectral lines.
A-Level Question 4. What is LASIK? A-Level
Answer: LASIK is Laser-Assisted In Situ Keratomileusis, a surgery that reshapes the cornea to correct vision.
A-Level Question 5. Why is an excimer laser used in LASIK? A-Level
Answer: Excimer UV lasers remove corneal tissue very precisely with minimal thermal damage.
A-Level Question 6. What are CFCs? A-Level
Answer: Chlorofluorocarbons are chemicals that release chlorine in the stratosphere and destroy ozone.
A-Level Question 7. What is ozone hole? A-Level
Answer: It is a severe seasonal thinning of ozone concentration, especially over polar regions.
A-Level Question 8. How does UV help forensic science? A-Level
Answer: Many body fluids, fibres and security inks fluoresce under UV light.
A-Level Question 9. How does UV help currency detection? A-Level
Answer: Security markings on notes fluoresce under UV radiation.
A-Level Question 10. Why is direct UV-C exposure dangerous? A-Level
Answer: It can damage skin and eyes because it is strongly absorbed by biological molecules.
A-Level Question 11. What is photoelectric detection of UV? A-Level
Answer: UV photons eject electrons from suitable surfaces, producing a measurable current.
A-Level Question 12. Why does UV sterilize water? A-Level
Answer: UV-C damages genetic material of microorganisms in water.
A-Level Question 13. Why is the Sun a source of UV? A-Level
Answer: The hot solar photosphere and chromosphere emit radiation over a broad spectrum including UV.
A-Level Question 14. What is the frequency range of UV? A-Level
Answer: Approximately 7.5×10^14 Hz to 3×10^15 Hz.
A-Level Question 15. What is the wavelength range of UV? A-Level
Answer: Approximately 100 nm to 400 nm.
A-Level Question 16. Why is UV invisible? A-Level
Answer: Human photoreceptors do not respond to wavelengths shorter than visible violet.
A-Level Question 17. What is UV-A associated with? A-Level
Answer: UV-A is strongly associated with aging and tanning effects.
A-Level Question 18. What is UV-B associated with? A-Level
Answer: UV-B is associated with burning, sunburn and direct DNA damage.
Section 20: Case Studies Case Study 1: Ozone Layer Protection Passage: The ozone layer absorbs harmful ultraviolet radiation and protects life on Earth.
Ozone Layer Protection
Case 1.1. Why is UV more energetic than visible light? Case Study
Detailed Answer: Photon energy E = hc/λ, and UV has shorter wavelength than visible light.
Case 1.2. Why is UV-C germicidal? Case Study
Detailed Answer: UV-C has enough photon energy to damage DNA and RNA of microorganisms, preventing reproduction.
Case 1.3. Why does ozone protect life? Case Study
Detailed Answer: Ozone absorbs most harmful UV-B and UV-C radiation before it reaches Earth surface.
Case 1.4. What is ozone layer? Case Study
Detailed Answer: It is a region in the stratosphere with relatively high ozone concentration.
Case 1.5. Why can UV damage eyes? Case Study
Detailed Answer: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
Case Study 2: LASIK Surgery Passage: Excimer UV laser reshapes the cornea with high precision.
LASIK Surgery
Case 2.1. Why is UV-C germicidal? Case Study
Detailed Answer: UV-C has enough photon energy to damage DNA and RNA of microorganisms, preventing reproduction.
Case 2.2. Why does ozone protect life? Case Study
Detailed Answer: Ozone absorbs most harmful UV-B and UV-C radiation before it reaches Earth surface.
Case 2.3. What is ozone layer? Case Study
Detailed Answer: It is a region in the stratosphere with relatively high ozone concentration.
Case 2.4. Why can UV damage eyes? Case Study
Detailed Answer: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
Case 2.5. Why does UV cause sunburn? Case Study
Detailed Answer: UV-B can damage skin cells and trigger inflammation, producing sunburn.
Case Study 3: UV Sterilization in Hospitals Passage: UV-C lamps disinfect air, surfaces and instruments when used safely.
UV Sterilization in Hospitals
Case 3.1. Why does ozone protect life? Case Study
Detailed Answer: Ozone absorbs most harmful UV-B and UV-C radiation before it reaches Earth surface.
Case 3.2. What is ozone layer? Case Study
Detailed Answer: It is a region in the stratosphere with relatively high ozone concentration.
Case 3.3. Why can UV damage eyes? Case Study
Detailed Answer: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
Case 3.4. Why does UV cause sunburn? Case Study
Detailed Answer: UV-B can damage skin cells and trigger inflammation, producing sunburn.
Case 3.5. What is fluorescence? Case Study
Detailed Answer: Fluorescence is emission of visible light by a substance after absorbing higher-energy radiation such as UV.
Case Study 4: UV Radiation and Skin Cancer Passage: UV radiation can damage DNA and increase skin cancer risk.
UV Radiation and Skin Cancer
Case 4.1. What is ozone layer? Case Study
Detailed Answer: It is a region in the stratosphere with relatively high ozone concentration.
Case 4.2. Why can UV damage eyes? Case Study
Detailed Answer: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
Case 4.3. Why does UV cause sunburn? Case Study
Detailed Answer: UV-B can damage skin cells and trigger inflammation, producing sunburn.
Case 4.4. What is fluorescence? Case Study
Detailed Answer: Fluorescence is emission of visible light by a substance after absorbing higher-energy radiation such as UV.
Case 4.5. How are UV rays detected by photographic plates? Case Study
Detailed Answer: UV radiation can cause chemical changes in photographic materials, darkening the plate.
Case Study 5: Forensic Detection using UV Passage: UV light reveals fluorescence from inks, fibres and biological traces.
Forensic Detection using UV
Case 5.1. Why can UV damage eyes? Case Study
Detailed Answer: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
Case 5.2. Why does UV cause sunburn? Case Study
Detailed Answer: UV-B can damage skin cells and trigger inflammation, producing sunburn.
Case 5.3. What is fluorescence? Case Study
Detailed Answer: Fluorescence is emission of visible light by a substance after absorbing higher-energy radiation such as UV.
Case 5.4. How are UV rays detected by photographic plates? Case Study
Detailed Answer: UV radiation can cause chemical changes in photographic materials, darkening the plate.
Case 5.5. Why are mercury vapor lamps used for UV? Case Study
Detailed Answer: Excited mercury atoms emit strong ultraviolet spectral lines.
Section 21: PYQ Collection NEET PYQ-style 1. Why does ozone protect life? NEET
Detailed solution: Ozone absorbs most harmful UV-B and UV-C radiation before it reaches Earth surface.
NEET PYQ-style 2. What is ozone layer? NEET
Detailed solution: It is a region in the stratosphere with relatively high ozone concentration.
NEET PYQ-style 3. Why can UV damage eyes? NEET
Detailed solution: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
JEE Main PYQ-style 1. Why does ozone protect life? JEE Main
Detailed solution: Ozone absorbs most harmful UV-B and UV-C radiation before it reaches Earth surface.
JEE Main PYQ-style 2. What is ozone layer? JEE Main
Detailed solution: It is a region in the stratosphere with relatively high ozone concentration.
JEE Main PYQ-style 3. Why can UV damage eyes? JEE Main
Detailed solution: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
JEE Advanced PYQ-style 1. Why does ozone protect life? JEE Advanced
Detailed solution: Ozone absorbs most harmful UV-B and UV-C radiation before it reaches Earth surface.
JEE Advanced PYQ-style 2. What is ozone layer? JEE Advanced
Detailed solution: It is a region in the stratosphere with relatively high ozone concentration.
JEE Advanced PYQ-style 3. Why can UV damage eyes? JEE Advanced
Detailed solution: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
CBSE PYQ-style 1. Why does ozone protect life? CBSE
Detailed solution: Ozone absorbs most harmful UV-B and UV-C radiation before it reaches Earth surface.
CBSE PYQ-style 2. What is ozone layer? CBSE
Detailed solution: It is a region in the stratosphere with relatively high ozone concentration.
CBSE PYQ-style 3. Why can UV damage eyes? CBSE
Detailed solution: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
ICSE PYQ-style 1. Why does ozone protect life? ICSE
Detailed solution: Ozone absorbs most harmful UV-B and UV-C radiation before it reaches Earth surface.
ICSE PYQ-style 2. What is ozone layer? ICSE
Detailed solution: It is a region in the stratosphere with relatively high ozone concentration.
ICSE PYQ-style 3. Why can UV damage eyes? ICSE
Detailed solution: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
IGCSE PYQ-style 1. Why does ozone protect life? IGCSE
Detailed solution: Ozone absorbs most harmful UV-B and UV-C radiation before it reaches Earth surface.
IGCSE PYQ-style 2. What is ozone layer? IGCSE
Detailed solution: It is a region in the stratosphere with relatively high ozone concentration.
IGCSE PYQ-style 3. Why can UV damage eyes? IGCSE
Detailed solution: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
IB PYQ-style 1. Why does ozone protect life? IB
Detailed solution: Ozone absorbs most harmful UV-B and UV-C radiation before it reaches Earth surface.
IB PYQ-style 2. What is ozone layer? IB
Detailed solution: It is a region in the stratosphere with relatively high ozone concentration.
IB PYQ-style 3. Why can UV damage eyes? IB
Detailed solution: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
A-Level PYQ-style 1. Why does ozone protect life? A-Level
Detailed solution: Ozone absorbs most harmful UV-B and UV-C radiation before it reaches Earth surface.
A-Level PYQ-style 2. What is ozone layer? A-Level
Detailed solution: It is a region in the stratosphere with relatively high ozone concentration.
A-Level PYQ-style 3. Why can UV damage eyes? A-Level
Detailed solution: UV photons can damage cornea, lens and retinal tissues, increasing risk of cataract and other problems.
Section 22: Memory Tricks UV-A → Aging
UV-B → Burning
UV-C → Cleaning
Ozone trick
Section 23: Exam Revision Sheet Most important formulas c = νλ E = hν E = hc/λ
Most important facts
Most repeated questions
LASIK summary
Section 24: Common Student Mistakes Mistake 1
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Mistake 3
Mistake 4
Mistake 5
Mistake 6
Mistake 7
Mistake 8
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Mistake 10
Mistake 11
Mistake 12
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Mistake 17
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Mistake 20
