Exercises

States Newton's formula for velocity of sound.

What is the effect of pressure on velocity of sound?

What is the effect of humidity of air on velocity of sound?

What do you mean by an echo?

State any two application of acoustics

Define amplitude and wavelength of a wave.

Draw a wave length and indicate points which are in phase. 

The sound emitted from the siren of an ambulance has frequency of $1500 \mathrm{Hz}$. The speed of sound is $340 \mathrm{m}/\mathrm{s}$. Calculate the difference in frequencies heard by a stationary observer, when the ambulance initially, travels towards and then away from the observer at a speed of $30 \mathrm{m}/\mathrm{s}$.