Statement-1 : Pendulum clocks go slow in summer and fast in winter.
Statement-2 : The length of the pendulum used in clock increases in summer.

Options

A. Statement-1 is True, Statement-2 is True , Statement-2 is a corrrect explanation for Statement-1
B. Statement-1 is True, Statement-2 is True , Statement-2 is NOT a corrrect explanation for Statement-1
C. Statement-1 is True, Statement-2 is False.
D. Statement-1 is False, Statement-2 is True.

Answer

To solve the problem, we need to analyze both statements regarding the behavior of pendulum clocks in different seasons.

### Step-by-Step Solution:

1. **Understanding the Pendulum Motion**:
- The time period \( T \) of a simple pendulum is given by the formula:
\[ T = 2\pi \sqrt{\frac{L}{g}} \]
where \( L \) is the length of the pendulum and \( g \) is the acceleration due to gravity.

2. **Effect of Temperature on Length**:
- In summer, the temperature is higher, which causes thermal expansion of materials. For a pendulum, this means that the length \( L \) of the pendulum increases.
- The change in length due to thermal expansion can be expressed as:
\[ \Delta L = L \alpha \Delta T \]
where \( \alpha \) is the coefficient of linear expansion and \( \Delta T \) is the change in temperature.

3. **Analyzing the Impact on Time Period**:
- Since the length \( L \) increases in summer, we can conclude that:
\[ T \propto \sqrt{L} \]
- Therefore, if \( L \) increases, \( T \) also increases. This means that the time taken for one complete oscillation of the pendulum is longer.

4. **Conclusion about Clock Behavior**:
- A longer time period \( T \) means that the pendulum clock will take more time to complete one oscillation, which results in the clock running slower.
- Conversely, in winter, when the temperature is lower, the length of the pendulum decreases, leading to a shorter time period \( T \) and thus the clock runs faster.

5. **Final Evaluation of Statements**:
- **Statement 1**: "Pendulum clocks go slow in summer and fast in winter" is true.
- **Statement 2**: "The length of the pendulum used in clock increases in summer" is also true.
- Therefore, Statement 2 correctly explains Statement 1.

### Final Answer:
Both statements are true, and Statement 2 is the correct explanation of Statement 1.

---