Apparatus required:
A source of sound pulses, a measuring tape, a sound receiver, and a stopwatch.
Procedure:
- Measure the distance d between the source of sound pulse and the reflecting surface using the measuring tape.
- The receiver is also placed adjacent to the source. A sound pulse is emitted by the source.
- The stopwatch is used to note the time interval between the instant at which the sound pulse is sent and the instant at which the echo is received by the receiver. Note the time interval as ‘t’.
- Repeat the experiment for three or four times. The average time taken for the given number of pulses is calculated.
Calculation of speed of sound:
- The sound pulse emitted by the source travels a total distance of 2d while travelling from the source to the wall and then back to the receiver.
- The time taken for this has been observed to be ‘t’. Hence, the speed of the sound wave is given by:
Speed of sound = \(\frac{Distance\, travelled}{Time\,taken} = \frac{2d}{t}\)
