The correct option is (c).
Explanation
The atmosphere is divided into five distinct layers based on temperature and composition: Troposphere, Stratosphere, Mesosphere, Thermosphere, and Exosphere. The Thermosphere is the fourth layer, characterized by high temperatures and the presence of ionized particles.
Statement-wise Analysis
- Statement 1 is Correct: The Thermosphere is located immediately above the Mesosphere. The boundary separating the Mesosphere and the Thermosphere is known as the Mesopause. It extends from approximately 80 km to 400 km above the Earth's surface.
- Statement 2 is Incorrect: The Thermosphere contains a layer known as the Ionosphere, which consists of electrically charged particles (ions). This layer reflects radio waves back to the Earth, facilitating long-distance wireless and radio communication. It does not block radio waves; rather, it aids in their propagation around the curvature of the Earth.
- Statement 3 is Correct: In the Thermosphere, temperature rises very rapidly with increasing height. This sharp increase is due to the absorption of intense solar radiation, specifically ultraviolet (UV) and X-ray radiation, by the gas molecules in this layer. Temperatures here can reach up to 2,000°C or higher.
Key Takeaway: The Thermosphere lies above the Mesosphere and is characterized by a rapid increase in temperature with altitude. It houses the Ionosphere, which reflects radio waves to Earth, enabling radio communication.