The speed of a compressional wave in air at standard temperature and pressure is

PHYSICS · Multi-part · A Level · Physics · Waves · Waves

Problem

330\,\mathrm{m/s}

. A point source of frequency

300\,\mathrm{Hz}

radiates energy uniformly in all directions at a rate of

5\,\mathrm{W}

. (a) What is the intensity of the wave at a distance of

20\,\mathrm{m}

from the source? (b) What is the amplitude of the wave there? Density of air at STP is

1.29\,\mathrm{kg/m^3}