Fountain ink pen leaks at higher altitudes. It is due to

Options

A. low atmospheric pressure
B. high temperatures
C. high atmospheric pressure
D. Both (a) and (b)

Explanation

### Step-by-Step Solution:

1. **Understanding the Problem**: The question asks why fountain ink pens leak at higher altitudes. We need to analyze the conditions that change when we ascend to higher elevations.

2. **Observing Changes in Altitude**: As we go to higher altitudes, such as climbing mountains, we experience a change in atmospheric conditions. Specifically, we need to focus on atmospheric pressure.

3. **Effect of Altitude on Atmospheric Pressure**: At higher altitudes, the atmospheric pressure decreases. This means that the pressure surrounding the fountain pen is lower than it is at sea level.

4. **Pressure Inside the Fountain Pen**: The fountain pen is designed to maintain a certain amount of pressure inside it to keep the ink from leaking. When we are at sea level, the pressure inside the pen is balanced with the external atmospheric pressure.

5. **Pressure Imbalance**: When we ascend to higher altitudes and the external atmospheric pressure decreases, the pressure inside the fountain pen remains higher than the outside pressure. This pressure imbalance causes the ink to be forced out of the pen.

6. **Conclusion**: Therefore, the reason why fountain ink pens leak at higher altitudes is due to low atmospheric pressure. The internal pressure of the pen exceeds the external pressure, leading to leakage.

### Final Answer:
The fountain ink pen leaks at higher altitudes due to low atmospheric pressure.

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