Hi,

You should not go too deep into the theory but just memorize the formulae & solve problems.

Some topics of this chapter which are very important are:

1. Doppler Effect
2. Stationary wave
3. Factors Affecting speed of sound

Solve lots of problem on Doppler Effect.

Its actually very interesting topic if you understand it and its hell if you try to mug up things. So take your time, go to some good theory books, go to your Physics instructor and understand the concepts.

As far as JEE is concerned they give too much concern to Doppler effect specifically but you can’t predict what JEE people will ask! But wave as whole is important topic. Remember don’t try to mug up formulae (if you understand concepts then you’ll find them very easy).

Hope this helps.

All the best.