Which of the following is the coldest layer?

Options

A. Troposphere
B. Mesosphere
C. Stratosphere
D. thermosphere

Answer

To determine which layer of the atmosphere is the coldest, we can follow these steps:

### Step 1: Identify the Layers of the Atmosphere
The atmosphere is divided into several layers, which include:
- Troposphere
- Stratosphere
- Mesosphere
- Thermosphere

### Step 2: Understand the Temperature Characteristics of Each Layer
- **Troposphere**: This is the lowest layer where weather occurs. The temperature decreases with altitude, typically ranging from about 15°C at sea level to about -50°C at the top.
- **Stratosphere**: Above the troposphere, the temperature increases with altitude due to the absorption of ultraviolet radiation by the ozone layer. The temperature can reach around 0°C at the stratopause (the top of the stratosphere).
- **Mesosphere**: This layer is above the stratosphere. The temperature decreases with altitude, reaching its minimum at about -100°C at the mesopause (the top of the mesosphere).
- **Thermosphere**: Above the mesosphere, the temperature increases significantly due to solar radiation, reaching up to 1200°C or higher.

### Step 3: Compare the Temperature Ranges
From the information gathered:
- The **troposphere** has temperatures down to about -50°C.
- The **stratosphere** can reach around 0°C.
- The **mesosphere** has temperatures that can drop to about -100°C.
- The **thermosphere** has very high temperatures, reaching up to 1200°C.

### Step 4: Conclusion
Based on the temperature characteristics, the coldest layer of the atmosphere is the **mesosphere**, with temperatures reaching as low as -100°C.

### Final Answer
The coldest layer of the atmosphere is the **mesosphere**.

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