prep 2 , unit 2 , lesson 2

Ozone layer is located in .......... layer.

• troposphere

• stratosphere

• mesosphere

• thermosphere

Ozone gas molecule consists of ............

• four oxygen atoms.

• two oxygen atoms.

• three oxygen atoms.

• one oxygen atom.

Oxygen molecule splits into two free atoms in the stratosphere layer under the effect

• heat.

• infrared radiations.

• ultraviolet radiations.

• cooling down.

Scientist proposed that the thickness of ozone layer is about 3 mm under the standard temperature and pressure.

• Newton

• Edeson

• Dobson

• Watson

Ozone degree is measured in a unit called

• km.

• Dobson.

• mm³

• nm.

One Dobson unit is defined as

• 3 mm.

• 0.1 mm.

• 0.01 mm.

• 0.001 mm.

Ozone layer absorbs...........

• infrared rays.

• ultraviolet rays.

• X-ray.

• light rays.

The ozone layer does not allow the passage ultraviolet rays.

• far

• medium

• near

• normal

Ozone layer allows 100% of the........... UV rays to penetrate the Earth's atmosphere.

• far

• medium

• near

• normal

Nanometre equals........... metre.

• 1 x 10-3

• 1 x 10-6

• 1 x 10-9

• 1 x 10-12