where d is the distance between the centres of the two slits (See Figure 1).

The intensity of the interference pattern produced by two sources is simply varied by the diffraction effects.

We will have cos

A double slit of width 0.5 mm is illuminated with light of wavelength 550 nm. Calculate the diffraction angle for the second maximum.

Using ml = d sin q with m = 2

we have sin q = 2 x 5.5x10

Therefore angle of diffraction = 0.13