The waves produced by motor boat sailing on water are

Ultrasonic waves are produced by making use of

Which among the following is true for propagation of sound waves ?

What is the phenomenon where sound waves bounce off a surface called?

A sound wave travelling at a speed of 330 m/s produces 20 crests and 20 troughs in 0.1 second. The wavelength (λ) of the sound wave is:

Which of the following is not a musical instrument that produces sound by vibrating a string?