Two coherent sources emit waves of 2.0-m wavelength in phase.If the path length to an observer differs by ________,then _________ interference occurs.
A) 1.0 m,constructive
B) 2.0 m,destructive
C) 3.5 m,constructive
D) 7.0 m,destructive
E) 8.0 m,destructive

Question

Quizplus · Accepted Answer

The path difference between the two sources must be equal to an integer multiple of the wavelength for constructive interference to occur and an odd multiple of the half-wavelength for destructive interference. Since the wavelength is 2.0 m, the path difference should be 2n*2.0 m for constructive interference and (2n+1)*1.0 m for destructive interference, where n is an integer. Therefore, the only option where destructive interference occurs is D, where the path length difference is 7.0 m.

Two Coherent Sources Emit Waves of 2