Aparallel beam of sodium lignt falls normally of a plane grating having 4240 lines per cm
Channel: Doubtnut
Date: 2021-11-02

Aparallel beam of sodium lignt falls normally of a plane grating having 4240 lines per cm. A second order line is obseved at `30^(@)` to the normal. Find the wavelength. What is the highest order that can be observed with this grating? Will this line appear to be of the same colour in each order ?