Question

When a thin transparent plate of thickness $$t$$ and refractive index $$\mu$$ is placed in the path of one of the two interfering waves of light, then the path difference changes by

Answer 1

Correct option is B. $$(\mu -1)t$$
Let $$S_1$$ and $$S_2$$ be two virtual conherent sources which are producing interference.

Refer image,

If a thin transperent plate of thickness t be introduces into one of the paths (say $$S_1P$$) of the interfering rays, then the position of the central frigne willl be shifter from C to P (say), so that the joptica; path $$S_1P$$ is again equa; to the optical path $$S_2P$$

Thw time taken by light in