Question

Radio waves which are directed towards the sky from a transmitter at a certain location on the earth

and are reflected back from the ionosphere towards another location on the earth are called sky waves.

The transmission of information through sky waves is called sky wave propagation (or

communication). Ionosphere is the upper most layers in the earth’s atmosphere extending from a

height of 80km to 300km above the surface of the earth. The ionosphere is composed of charged

particles (electrons and ions). The degree of ionization is less at layers of ionosphere closer to the earth

than at the layers away from the earth. Consequently, the refractive index of the lower most layers of

the ionosphere is the highest and it decreases as we go to the upper layers.

Based on the above passage answer the following questions:

1. The gases in the ionosphere are ionized by

a) Ultraviolet and high frequency radiations from the sun

b) Infrared thermal radiations from the sun

c) Sunlight reflected from the earth

d) Global warming​

Answer 1

Answer:

1 thermosphere

2 ozone

3 exosphere

4 surface of the earth

5 because of harmful gases