A layer in the Earth’s atmosphere called the ionosphere facilitates radio communication. Why?

1. The presence of ozone causes the reflection of radio waves to earth.
2. Radio waves have a very long wavelength.

Which of the statements given above is/are correct?

1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2

Explanation

Statement 1 is incorrect

• The Ionosphere facilitates long-distance radio communication because it contains a large number of ionized particles (free electrons and ions) created by the action of solar radiation. These charged particles reflect or refract radio waves back toward the Earth, allowing signals to travel beyond the horizon.
• The reflection of radio waves in the ionosphere is not due to the presence of ozone. Ozone is mainly concentrated in the Stratosphere, where it absorbs harmful ultraviolet radiation. The ionosphere’s ability to reflect radio waves is due to ionization, not ozone.

Statement 2 is incorrect:

• Although many radio waves used for communication have long wavelengths, this is not the reason the ionosphere facilitates radio communication. The key factor is the interaction of radio waves with ionized particles, not merely their wavelength.

Answer: (d) Neither 1 nor 2 | Difficulty Level: Medium