The center spot of Newton's rings is dark.This destructive interference occurs because:
A)the two beams travel distances that are different by half a wavelength.
B)both waves change phase by 180° as they are reflected.
C)one beam changes phase by 180° when it is reflected.
D)both waves have a trough.

Question

Quizplus · Accepted Answer

When a beam of light is reflected from the top and bottom surfaces of the thin film, the waves interfere with each other. The two reflected waves change phase by 180 degrees because one of the waves reflects from a medium with a higher refractive index, while the other reflects from a medium with a lower refractive index. When the two waves interfere, there is a phase difference of 180 degrees, causing destructive interference at the center of the Newton's rings, resulting in a dark spot. This is known as reflected wave interference.

The Center Spot of Newton's Rings Is Dark