What is mean by reflection of sound? Explain:
a) reflection at the boundary of a rarer medium
b) reflection at the boundary of a denser medium
c) Reflection at curved surfaces

What is an echo?
a) State two conditions necessary for hearing an echo.
b) What are the medical applications of echo?
c) How can you calculate the speed of sound using echo?

When sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound remain the same. Do you hear an echo sound on a hotter day? Justify your answer.

A source producing a sound of frequency 500 Hz is moving towards a listener with a velocity of 30 m s^–1. The speed of the sound is 330 m s^–1. What will be the frequency heard by listener?

A source and listener are both moving towards each other with a speed v/10 where v is the speed of sound. If the frequency of the note emitted by the source is f, what will be the frequency heard by the listener?