We can distinguish between the musical sounds produced by different singers on the basis of the characteristic of sound called:

A. frequency B. timbre

C. pitch D. loudness

Which of the following device does not work on the multiple reflections of sound waves?

A. stethoscope B. hydrophone

C. soundboard D. megaphone

What type of waves are generated by SONAR device fixed to a fishing ship?

A. water waves B. radio waves

C. sound wavesD. infrared waves

At 20°C, the minimum distance of a person from a sound reflecting surface to hear an echo is :

A. 12.2 m B. 17.2 m

C. 15.2 m D. 34.4 m

The drawing shoes a ship 800 m from a cliff. A gun is fired on the ship. After 5 seconds the people at the front of the ship hear the sound of the gun again.

(a) What is the name of this effect?

(b) What happens to the sound at the cliff?

(c) How far foes the sound travel in 5 seconds?

(d) Calculate the speed of sound.