Question

Sonar is a device for
(A) Location and ranging of aircrafts
(B) Location and ranging of submarines
(C) Producing a musical note of high quality
(D) Measuring frequency of musical notes

Answer 1

Hint: SONAR is the device used for locating the position in the deep sea by using the sound waves. This device works under the principle of the echolocation how the bats do, used for the location of the underwater objects from the time taken and the speed of the sound waves.
Useful formula:
The formula of the distance is given by
$d = vt$
Where $d$ is the distance of the object, $v$ is the velocity of the sound waves and $t$ is the time taken.

Complete answer:
SONAR is the sound navigation and the ranging device. In this process, the principle of the reflection of the sound is used for the purpose of finding the location of the submarines in the deep sea. The sound may be infrasonic, audible and the ultrasonic types. Out of which, the ultrasonic sound waves are used in the SONAR. This device transmits the ultrasonic waves into the deep sea, this waves moves down until there is any interruption due to any objects like submarines etc. The distance of the location is found by using the values of the speed of the ultrasonic waves and the time taken by it. The time taken is obtained in the form of the waves reaching the target and returns back. This half of this time is taken to find the distance using the formula.
$d = vt$
Hence the sonar is used for the location and the ranging of the submarines.

Thus the option (B) is correct.

Note:
The sonar is used in two ways as the active sonar and the active sonar. The passive sonar listens only to the sounds made by the objects like vessels in the deep sea and the active sonar sends the sound waves and listens back to find its location.