Question

Light travels from outside a building to inside through a pane of glass. There are therefore two interfaces where reflection can happen. One on the outside (when the light passes into the glass) and on the inside (when the light passes from the glass back into air). If the light is reflected back outside, how many phase changes occur? Which interface(s) does the phase change(s) occur? Explain your answer.

Answer 1

Solution:---

1. When light travels from rare medium to denser medium then there is phase difference of π rad between incident light and reflected light. While no phase difference between incident light and retracted ( transmitted through medium) light.

So when light enters from air to glass then a phase difference of π occurred between incident light and retracted light.

​​2. When light travels from denser medium to rare medium then there is no phase difference between incident light and reflected light . And also there is no phase difference between incident light and retracted (transmitted) light.

So there will be no phase difference occur between incident light and reflected light.