Monochromatic light (λ = 500 nm) is incident on a soap bubble (n = 1.4) that is 50 mm thick. What is the change of phase of the light reflected from the front surface?
A) 0
B) 180°
C) λ/2
D) π/2
E) 55°

Question

Quizplus · Accepted Answer

The change of phase of light reflected from the front surface of a medium with a higher refractive index than the incident medium (air in this case) is 180°. This is a basic principle of wave optics, where reflection at the boundary of a denser medium leads to a half-wavelength (λ/2) phase shift, which is equivalent to 180°.

Monochromatic Light (λ = 500 Nm) Is Incident on a Soap