Q. Explain Construction of michelsons interferometer?

It consists of two highly polished plane mirror M1 and M2, with two optically plane glass plate G₁ and G₂ which are of same material and same thickness. The mirror M1 and M2 are adjusted in such a way that they are mutually perpendicular to each other. The plate G₁ and G₂ are exactly parallel to each other and placed at 45° to mirror M₁ and M₂. Plate G₁ is half silvered from its back while G₂ is plane and act as compensating plate. Plate G₁ is known as beam-splitter plate.

The mirror M₂ with screw on its back can slightly titled about vertical and horizontal direction to make it exactly perpendicular to mirror M₁. The mirror M₁ can be moved forward or backward with the help of micrometer screw and this movement can be measured very accurately.