About `20km` above the earth ,there is an ozone layer ,Which one of the following statement about ozone and ozone layer is true?

Options

A. Convesion of `O_(3)` to `O_(2)` is an endothermic process
B. Ozone is a triatomic linear moleucles
C. it is benficial to us as it stops `UV` radiation
D. it is harmful as it stops useful radiation

Answer

3

Explanation

Ozone is present in the upper atmosphere (about `20km` from the surface of earth ) where it is formed by the action of ultravioet `(UV)` radiations on dioxygen:
`3O_(2) overset("Uv light")rarr2O_(3)`
Ozones absorbs `UV` radiations `(220-290 nm)` and thus protects the earth and its inhabitants from the harmful radiations of the sun,if there were no `O_(3)` layer more `UV` radiations will reach the sun earth's surface causing much damage to plant and animal life.