Fluffy materials ....................... (absorb/reflect) sound.

Clothes and paper ..................(reflect/absorb) sound.

State two laws of reflection of sound.

State one use of reflection of sound.

A sound waves passes from a medium A to a medium B . The velocity of sound in B is greater than in A . Assume that there is no absorption or reflection at the boundary . As the wave moves across the boundary :

The sound heard after reflection is............

What do you mean by reflection of sound?

There are materials which absorb photon of shorter wavelength and emit photons of longer wavelength. Can there be stable substances which absorb photons of larger wavelength and emit light of shorter wavelength.

A man standing 25 m away from a wall produces a sound and receives the reflected sound. Will the man be able to hear a distinct echo ? Give a reason for your answer.

Name three different materials which absorb sound.

A man standing 25 m away from a wall produces a sound and receives the reflected sound. Calculate the time after which he receives the reflected sound if the speed of sound in air is 350ms^(-1) .