The uppermost layer of the atmosphere, in which temperature increases as altitude increases.

The uppermost layer of the atmosphere, in which temperature increases as altitude increases.

• A. Troposphere
• B. Stratosphere
• C. Thermosphere
• D. Exosphere

Answer: (C)

As altitude increases, temperature in different atmospheric layers behaves differently. The troposphere cools as you go up, so its temperature drops with height. In the stratosphere, temperature actually rises with altitude because ozone absorbs UV radiation and heats the surrounding air. Above that, in the thermosphere, the heating continues and temperature climbs with height because high-energy solar radiation (UV and X-rays) heats the few particles present, even though the air is extremely thin. This makes the thermosphere the uppermost layer where you still see a clear increase in temperature with altitude. Beyond it, in the exosphere, the concept of temperature becomes less meaningful due to extremely low density. Therefore, the thermosphere is the correct layer.

As altitude increases, temperature in different atmospheric layers behaves differently. The troposphere cools as you go up, so its temperature drops with height. In the stratosphere, temperature actually rises with altitude because ozone absorbs UV radiation and heats the surrounding air. Above that, in the thermosphere, the heating continues and temperature climbs with height because high-energy solar radiation (UV and X-rays) heats the few particles present, even though the air is extremely thin. This makes the thermosphere the uppermost layer where you still see a clear increase in temperature with altitude. Beyond it, in the exosphere, the concept of temperature becomes less meaningful due to extremely low density. Therefore, the thermosphere is the correct layer.