Problem: Two rectangular pieces of plane glass are laid one upon the other on a table. A thin strip of paper is placed between them at one edge so that a very thin wedge of air is formed. The plates are illuminated at normal incidence by 550nm light from a mercury-vapor lamp. Interference fringes are formed, with 12.0 fringes per centimeter.
Part A: Find the angle of the wedge?
I just want the right answer, Thank you!