the minimum distance between the reflecting surface and source for listening the eco of sound is ( take speed of sound 340` m/s`)

Options

A. 34 m
B. 8.5 m
C. 17 m
D. 28 m

Answer

To find the minimum distance between the reflecting surface and the source for listening to the echo of sound, we can follow these steps:

### Step 1: Understand the concept of echo
An echo is the reflection of sound that is heard after a certain time delay. For an echo to be heard distinctly, the sound must travel to the reflecting surface and back to the source, taking at least 0.1 seconds.

### Step 2: Use the speed of sound
The speed of sound is given as 340 m/s. This means sound travels 340 meters in one second.

### Step 3: Calculate the distance sound travels in 0.1 seconds
To find out how far sound travels in 0.1 seconds, we can use the formula:
\[ \text{Distance} = \text{Speed} \times \text{Time} \]
Substituting the values:
\[ \text{Distance} = 340 \, \text{m/s} \times 0.1 \, \text{s} = 34 \, \text{meters} \]

### Step 4: Determine the minimum distance to the reflecting surface
The distance calculated (34 meters) is the total distance for the sound to travel to the reflecting surface and back. Therefore, to find the minimum distance to the reflecting surface, we divide this distance by 2:
\[ \text{Minimum Distance} = \frac{34 \, \text{meters}}{2} = 17 \, \text{meters} \]

### Conclusion
Thus, the minimum distance between the reflecting surface and the source for listening to the echo of sound is **17 meters**.

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