Physlet Illustration: Diffraction Grating

 

 
l = mm d = mm
In this simulation,  a diffraction grating is made, consisting of five slits located just below the edge of the screen. You may vary both the wavelength of light and the slit separation. The resulting interference may be observed in the ripples of the waves that propagate in the tank. Angles at which constructive interference occurs are characterized by bright intensity. At what angles does this occur?

Hints:

  1. Change the slit separation. (0.5 mm < d < 2 mm) How does it affect the interference pattern?
  2. Change the "color" of the light (i.e. the wavelength, 0.1 mm < l < 0.9 mm). How does it affect the interference pattern?
  3. What quantitative expression relates the angles of the diffraction maxima with d and l?

Reference

See Walker, Section 28-6

Illustration written by Steve Mellema