In a two-slit experiment with monochromatic light, fringes are obtained on a screen placed at some distance from the slits. If the screen is moved by `5xx10^(-2)` m towards the slits, the change in fringe width is `3xx10^(-5)`. If the distance between the slits is `10^(-3)`m, calculate the wavelength of the light used.

Explanation

The wavelength of the light for which intensity falls to zero for the smallest angle is `lambda = a sintheta`( condition of first minima)
  Substituting a = `6.0 xx 10^(-5) m` and `theta` =`(0.11xx180^(@))/(pi)=0.63^(@))`, we get
`lambda = 6.0 xx 10^(-6) m sin 0.63^(@) = 660 nm`