Question

The region of atmosphere having the constant temperature is

• A. Troposphere
• B. Mesopause
• C. Stratosphere
• D. Ionosphere

Hint:

Think about which atmospheric layer has a nearly flat temperature profile before the ozone driven rise begins.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks which layer of the atmosphere is known for having a fairly constant temperature with height.

Step 2: Key Formula or Approach:
Temperature does not change the same way in every atmospheric layer. In the troposphere, temperature falls steadily as you go up. In the stratosphere, the lower part stays nearly constant with height before temperature starts rising again due to ozone absorbing ultraviolet radiation. This near constant lower band is why the stratosphere is picked out as the layer of steady temperature in most basic classifications of the atmosphere.

Step 3: Detailed Explanation:
Option (1), Troposphere: temperature keeps falling with height here, at roughly 6.5 degrees Celsius per km, so it is not constant.
Option (2), Mesopause: this is only a thin boundary line at the top of the mesosphere, marking the coldest point of the atmosphere, not a broad region with constant temperature.
Option (3), Stratosphere: its lower part is essentially isothermal, holding a fairly steady temperature before rising higher up due to ozone. Among the four choices, this is the layer conventionally described as having a constant temperature.
Option (4), Ionosphere: temperature rises sharply here due to absorption of solar radiation by charged particles, so it is not constant.

Step 4: Final Answer:
The stratosphere is the layer known for its constant temperature zone, so option (3) is correct.