8.2.2

Intensity of Waves

Test yourself

Intensity of Progressive Waves

The intensity of any wave is defined as the time-averaged power transferred per area of space. The intensity is proportional to the square of the amplitude of the wave.

Illustrative background for Intensity and powerIllustrative background for Intensity and power ?? "content

Intensity and power

  • By definition, the intensity (I) of any wave is the time-averaged power (P) it transfers per area (A) through some region of space.
  • The units of intensity are therefore Watts per square metre (Wm-2).
Illustrative background for Intensity and amplitudeIllustrative background for Intensity and amplitude ?? "content

Intensity and amplitude

  • The energy of a wave is proportional to the square of its amplitude. Therefore the intensity of a wave is also proportional to the square of its amplitude.
Illustrative background for ImplicationIllustrative background for Implication ?? "content

Implication

  • We often deal with waves propagating through space, where the intensity varies as an inverse square law with distance from the source of the waves.
  • Therefore, the amplitude of the wave must fall as a simple inverse proportion to distance.

Jump to other topics

1Physical Quantities & Units

2Measurement Techniques

3Kinematics

4Dynamics

5Gravitational Fields

6Deformation of Solids

7Thermal Physics

8Oscillations

9Communication

10Electric Fields

11Current Electricity

12Magnetic Fields

13Modern Physics

Unlock your full potential with Seneca Premium

  • Unlimited access to 10,000+ open-ended exam questions

  • Mini-mock exams based on your study history

  • Unlock 800+ premium courses & e-books

Get started with Seneca Premium