Q. Show Function of Compensating Plate in interferometer?
In absence of plate G2 the reflected ray passes the plate G1 twice, whereas the transmitted ray does not passes even once. Therefore, the optical paths of the two rays are not equal. To equalize this path the plate G2 which is exactly same as the plate G1 is introduced in path of the ray proceeding towards mirror M2 that is why this plate is called compensating plate because it compensate the additional path difference.