A man sitting in a moving train hears the whistle of the engine. The frequency of the whistle is 600 Hz

Options

A. The apparent frequency as heard by him is smaller than 600 Hz
B. The apparent frequency is larger than 600 Hz
C. The frequency as heard by him is 600 Hz
D. none of the above

Answer

To solve the problem, we need to determine the apparent frequency of the whistle heard by a man sitting in a moving train when the actual frequency of the whistle is given as 600 Hz.

### Step-by-Step Solution:

1. **Identify the Given Information**:
- Frequency of the whistle (f₀) = 600 Hz
- The man is sitting in a moving train, which means both the source of sound (the whistle) and the observer (the man) are moving together with the same speed.

2. **Understand the Doppler Effect**:
- The Doppler effect describes how the frequency of sound changes for an observer moving relative to the source of the sound.
- If there is no relative motion between the source and the observer, the apparent frequency (f) heard by the observer will be equal to the actual frequency (f₀).

3. **Analyze the Situation**:
- Since the man is inside the train and both the source (whistle) and the observer (man) are moving at the same speed, there is no relative motion between them.
- Therefore, the Doppler effect does not apply in this case.

4. **Conclusion**:
- The apparent frequency (f) heard by the man will be equal to the actual frequency of the whistle.
- Thus, f = f₀ = 600 Hz.

5. **Final Answer**:
- The frequency heard by the person in the train is 600 Hz.