Q. 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 statements given above is/are correct? (UPSC Prelims 2011)
Answer:
1 only
Notes: The correct answer is
neither 1 nor 2.Both statements provided in the question are scientifically incorrect regarding why the ionosphere facilitates radio communication.
- Statement 1 is Incorrect: The Ozone layer is located in the Stratosphere, which is much lower than the Ionosphere. Furthermore, ozone does not reflect radio waves; its primary job is to absorb ultraviolet (UV) radiation. The reflection of radio waves is actually caused by free electrons and ions created by solar radiation in the Ionosphere.
- Statement 2 is Incorrect: While some radio waves (like Long Wave or Medium Wave) do have long wavelengths, the length of the wavelength is not the reason the Ionosphere facilitates communication. In fact, high-frequency radio waves (with shorter wavelengths) are the ones most famously reflected by the ionosphere to allow for long-distance "Shortwave" broadcasting.