(a) A mobile ringing inside a vacuum chamber cannot be heard outside. Why ? (b) Represent transverse wave graphically. (c) What is meant by loudness of sound ? On what factor does it depend?

(a) This is because sound requires a medium to travel.

(b) The graphical representation is as shown:

© Loudness is the measure of the response of the ear to the intensity of sound. It depends on the amplitude of the vibrating particle of the medium.