Question

Light of wavelength 600 nm illuminates a diffraction grating. The second order maximum is at an angle of 65 degrees. a) List your known variables. b) What is the spacing between slits in this grating? c) How many lines per millimeter does this grating have?

Answer 1

A. Known variables include

Wavelength = 600nm

Theta= 65°

m= 2

B.

d= m x wavelength / sin theta

= 2 * 600*10^-9 /sin 65°

= 1.3*10^-6m

C.

N = 1/d

So N = 1/1.3*10^-6m

=76.9 lines per micro meter