A rectangular block is composed of three different glass prisms (with refractive indices `mu_(1), mu_(2)` and `mu_(3)`) as shown in the figure below. A ray of light incident normal to the left face emerges normal to the right face. Then the refractive indices are related by

Options

A. `mu_(1)^(2)+mu_(2)^(2)=2mu_(3)^(2)`
B. `mu_(1)^(2)+mu_(2)^(2)=mu_(3)^(2)`
C. `mu_(1)^(2)+mu_(3)^(2)=2mu_(2)^(2)`
D. `mu_(2)^(2)+mu_(3)^(2)=2mu_(1)^(2)`

Answer

C