Question

Two identical waves undergo pure constructive interference. Is the resultant intensity twice that of the individual waves? Explain your answer.

a) Yes
b) No
c) It depends on amplitude
d) It depends on frequency

Answer 1

The resultant intensity of two identical waves that undergo pure constructive interference is four times that of the individual waves because intensity is proportional to the square of the amplitude.

Step-by-step explanation:

When two identical waves undergo pure constructive interference, the result isn't simply a doubling of the intensity; the intensity actually increases by a factor of four. This occurs because intensity is proportional to the square of the amplitude of the wave. In the case of pure constructive interference, the amplitudes of the waves add together, so if each individual wave has an amplitude of 'A', the combined wave has an amplitude of '2A'. The intensity of the combined wave is thus proportional to (2A)^2, which is 4A^2. Therefore, the resultant intensity is four times that of one individual wave's intensity, not just twice.