Question

When a beam of light that is traveling in air is reflected by a glass surface, there is

a.no phase change in the reflected beam.
b.a 90° phase change in the reflected beam.
c.a 180° phase change in the reflected beam.
d.a 45° phase change in the reflected beam.
e.a 60° phase change in the reflected beam.

Answer 1

A beam of light traveling in air and reflecting off a glass surface undergoes a 180° phase change in the reflected light.

Step-by-step explanation:

When a beam of light that is traveling in air is reflected by a glass surface, there is a 180° phase change in the reflected beam. This happens because light reflecting from a medium having an index of refraction greater than that of the medium (air in this case) it is traveling in, undergoes this phase change or a half wavelength (λ/2) shift. It is equivalent to the wave being inverted upon reflection at the boundary.