Light from a laser strikes a diffraction grating that has 5 308 grooves per centimeter. The central and first-order principal maxima are separated by 0.488 m on a wall 1.88 m from the grating. Determine the wavelength of the laser light. (In this problem, assume that the light is incident normally on the gratings.) nm

Solution :

Given :

The angle of the first maximum with the center is given by :

  = 14.5°

The grating distance can be calculated as :

   =

When the principal maxima yields at y = 0.488 m and the length from the wall 1.88 m. Thus the equation of the wavelength is :

 ,       where n = 1

the answer is f1 and d2 because if you put equal force on those two points the beam would balance trust me on this