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#ultraviolet radiation

2 public questions tagged with this topic.

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

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Ultraviolet, X-rays, Gamma Rays and Their Properties

What is the approximate wavelength range of ultraviolet rays as per the document?

**Ultraviolet** λ≈10-400 nm, produced by atomic transitions and Sun, causes fluorescence, sterilization, harmful to eyes/skin, absorbed by ozone layer. **X-rays** λ≈10⁻² to 10 nm, produced by rapid deceleration of energetic electrons in X-ray tube, used in medicine for diagnosis (shadow of bones) and cancer therapy due to high ionization and penetration, detected by photographic film and Geiger counter. The document states that ultraviolet rays range from about 400 nm to 0.6 nm . Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields 400 nm to 0.6 nm,

Ref: NCERT > Physics Book > Electromagnetic Waves > Ultraviolet, X-rays, Gamma Rays and Their Properties

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