Question

Read the following statements related to the side effects of UV-B radiation and select the incorrect statement.

• A. UV-B damages DNA and can lead to mutation
• B. UV-B can cause skin aging and skin cancers
• C. UV-B causes the inflammation of cornea which lead to snow-blindness
• D. UV-B has longer wavelength than the visible light

Answer 1

The correct option is D UV-B has longer wavelength than the visible light

Ultraviolet (UV) radiations have shorter wavelengths than the visible light. These are non-ionising radiations emitted by the sun.

UV radiation is of three types: UV-A (320 - 400 nm), UV-B (280 - 320 nm) and UV-C (200 - 280 nm).

UV-B may damage DNA and can lead to mutations. It also causes the aging of the skin and damages the skin cells which can lead to skin cancers.

Human eye possesses three layers: sclera (the outer layer), choroid (the middle layer) and retina (the inner layer).

Sclera is a tough, white and opaque layer. In the front part of the eye, the sclera is transparent and forms the cornea that covers the iris, pupil, etc.

Cornea absorbs UV-B radiation and a high dose of UV-B causes inflammation of the cornea which is called snow-blindness.

Hence, the statement in option d is incorrect.