Calculate the minimum distance in air required between the source of sound and the obstacle to hear an echo. Take speed of sound in air = 350 m`s^(-1)`

Explanation

To calculate the minimum distance required between the source of sound and the obstacle to hear an echo, we can follow these steps:

### Step 1: Understand the concept of echo
An echo is a reflection of sound that arrives at the listener after a delay. For us to perceive an echo, the time taken for the sound to travel to the obstacle and back to the source must be at least 0.1 seconds.

### Step 2: Use the formula for distance
The distance traveled by sound can be calculated using the formula:
\[ \text{Distance} = \text{Speed} \times \text{Time} \]
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