In SONAR we use:

A. ultrasonic waves

B. infrasonic waves

C. radio waves

D. audible sound waves

A sonar station picks up a return signal after 3 seconds. How far away is the object? (Speed of sound in water = 1440 m/s).

Draw a neat and labelled diagram of the human ear. With the help of this diagram, explain the construction and working of the human ear.

When we change a feeble sound to a loud sound, we increase its:

A. frequency B. amplitude

C. velocity D. wave length

Which kind of sound is produced in an earthquake before the main shock wave begins?

A. ultrasound B. infrasound

C. audible sound

D. none of the above