A layer in the Earth’s atmosphere called Ionosphere facilitates radio communication. Why?
- The presence of ozone causes the reflection of radio waves to Earth.
- Radio waves have a very long wavelength.
Which of the statement(s) given above is/are correct?
[UPSC Civil Services Exam – 2011 Prelims]
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer: (d)
Explanation:
- The ionosphere is an electrically charged layer located between 80 km and 400 km that is characterized by ionization of atoms. Due to its electric charge, it reflects radio waves transmitted from Earth. Temperature increases with height due to solar radiation.
- Statement 1 is incorrect because ozone is found in the stratosphere, not the ionosphere. Radio waves are a type of electromagnetic radiation with frequencies ranging from 3 kHz to 300 GHz and wavelengths from 1 millimetre to 100 kilometres. They are used in communication technologies like TV, mobile phones, and radios.
- Statement 2 is incorrect because radio waves have frequencies ranging from 3 kHz to 300 GHz, not up to 3 kHz.
Therefore, option (d) is the correct answer.
