CBSE Class 10 Science 2020 · Paper 31/2/3 · Question 18(a)

Our Environment 3 marks Easy

(a)State one important function of ozone layer at the higher level in the atmosphere.
(b)How is ozone formed ?
(c)It has been observed that ozone layer is getting depleted. Name the compound responsible for ozone depletion.

Answer

Ozone shields the Earth from UV; UV splits $O_{2}$ into atoms that form $O_{3}$ ; CFCs deplete it.

(a) The ozone layer shields the surface of the earth from the harmful ultraviolet (UV) radiation of the sun, which can cause skin cancer in human beings. (b) At the higher levels of the atmosphere, UV radiation from the sun splits oxygen molecules into free oxygen atoms, and each free oxygen atom then combines with an oxygen molecule to form ozone:

O_{2} UV O + O

and

O + O_{2} ⟶ O_{3}

. (c) Chlorofluorocarbons (CFCs), used as refrigerants and in fire extinguishers, are responsible for the depletion of the ozone layer.

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CBSE Class 10 Science 2020 · Paper 31/2/3 · Question 18(a)

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