Waves from two slits are in phase at the slits and travel to a distant screen to produce the third bright fringe of the interference pattern.The difference in the distance traveled by the waves is:
A)half a wavelength
B)a wavelength
C)three halves of a wavelength
D)two wavelengths
E)three wavelengths

Question

Quizplus · Accepted Answer

For the third bright fringe in an interference pattern, the path difference must be an integer multiple of the wavelength. Therefore, the path difference is three wavelengths.

Waves from Two Slits Are in Phase at the Slits