Question

A wave is reflected from a rigid support. The change in phase of reflection will be.
A. $\pi /4$
B. $\pi /2$
C. $\pi$
D. $2\pi$

Answer 1

When the light wave gets reflect from the surface of a medium with high refractive index than the medium they are traveling then the phase of lightwave changes by 180 degree the light wave will not undergo a phase change when they traveling in glass The phase is referred to as the electric field oscillations, not magnetic field oscillations

Complete step by step solution:
Light has an electromagnetic wave. They have a transverse magnetic component and a transverse electric component. because metal conducts electricity the electrical component can not enter into the metal
Let us consider attaching a piece of string to a solid and pushing a wave through by hand. We can see that when the wave hits the solid, it can not enter, and the end of the string does not move.
Here, the wave with the opposite phase wave starts at the attachment and comes towards you. Which is known as a reflected wave.
The same thing happens in light on a metal surface: to keep the total electric field parallel to the surface equal to zero, the surface needs to generate a wave in the opposite phase, it will reflect light.
So, the correct answer is option (A).

Note:
When a wave is reflected the phase change occurs
Light undergoes a phase change radians upon $\pi$ of $180^\circ$
When a light beam lies on a boundary of two media, one part of the light gets reflected and the other part of the light gets refracted.