PHYS 2211 Module 14.4

Energy and Power of a Wave

Recommended Reading

14.4 Energy and Power of a Wave

Learning Objectives

By the end of this section, you will be able to:

  • Explain how energy travels with a pulse or wave
  • Describe, using a mathematical expression, how the energy in a wave depends on the amplitude of the wave

Energy and Power in Waves


Three waves are traveling along identical strings.  Wave B has twice the amplitude of the other two.  Wave C has 1/2 the wavelength than A or B. Which wave, B or C, carries more energy per time (power)?

A sinusoidal wave on a string is described by the wave function:

where x and y are in meters and t is in seconds. The mass per unit length of this string is 12 g/m.

(a) Determine the speed of the wave.

(b) Determine the wavelength of the wave.

(c) Determine the frequency of the wave.

(d) Determine the power transmitted by the wave.