(i) What is the principle on which SONAR is based?
(ii) An observer stands at a certain distance away from a cliff and produces a loud sound. He hears the echo of the sound after $1.8 s$ . Calculate the distance between the cliff and the observer if the velocity of sound in air is $340 m s^{- 1}$ .

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Solution

(i) SONAR is based on the principle of reflection (echo) of sound waves from the object. It stands for Sound Navigation and Ranging.
(ii) Given : $v = 340 m / s$ , $t = 1.8 s$
Distance travelled by sound $= 2 d$
Distance $=$ speed $\times$ time
$2 d = v \times t$
$d = \frac{v \times t}{2}$
$= \frac{340 \times 1.8}{2} = 170 \times 1.8$
$= 306 m$ .
Therefore, the distance between the cliff and the observer is $306 m$ .

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(i) What is the principle on which SONAR is based?(ii) An observer stands at a certain distance away from a cliff and produces a loud sound. He hears the echo of the sound after 1.8s. Calculate the distance between the cliff and the observer if the velocity of sound in air is 340ms−1.

(i) What is the principle on which SONAR is based?
(ii) An observer stands at a certain distance away from a cliff and produces a loud sound. He hears the echo of the sound after $1.8 s$ . Calculate the distance between the cliff and the observer if the velocity of sound in air is $340 m s^{- 1}$ .