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#UV protection

4 public questions tagged with this topic.

What protects the Earth from most of the sun's ultraviolet radiation?

**Greenhouse effect** IR absorbed by CO₂, H₂O, CH₄, warming Earth, excessive greenhouse due to fossil fuel burning raises temperature, EM waves role: Sun visible reaches surface, Earth emits IR trapped, altering energy balance, safety concern for climate change. The document states that the ozone layer absorbs most of the ultraviolet radiation from the sun at an altitude of about 40-50 km . Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Ozone layer, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Environmental Effects - Ozone, Greenhouse and Safety

What protects the Earth from excessive ultraviolet radiation?

**Ozone absorbs UV** protecting life, depletion by CFCs, halons produces Cl· + O₃ → ClO + O₂, ClO + O → Cl· + O₂, catalytic cycle, one Cl destroys thousands of O₃, Montreal Protocol bans CFCs, UV increase harmful. The document mentions that the ozone layer absorbs most ultraviolet radiation from the sun at an altitude of 40-50 km . Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Ozone layer, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Environmental Effects - Ozone, Greenhouse and Safety

Why do welders wear special glass goggles during welding?

**Ozone layer depletion** environmental concern related to increased UV-B reaching surface, causing skin cancer, cataracts, damage to crops and marine life, due to CFCs releasing Cl that catalytically destroys O₃, O₃ absorbs UV 200-320 nm, depletion increases UV transmission. The document explains that welding arcs produce large amounts of UV radiation, and special glass goggles protect the eyes from this harmful radiation. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields To protect from UV radiation, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Environmental Effects - Ozone, Greenhouse and Safety

Flavonoids protect plants mainly from:

Answer: B) UV radiation. For PLANT SEC METABOLITES, remember the key idea and you’ll land on this option; the distractors usually swap cause and effect or confuse similar terms. Avoid: A) Herbivores; C) Pathogens; D) Salinity. Name the process first, then pick the option that describes it — don’t reverse cause and effect.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.