Question

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.

Answer 1

Correct Answer - `6000 Å`
As `beta = (lambda D)/(d) :. Delta beta = (lambda)/(d)(Delta D)`
`lambda = ((Delta beta) xx d)/(Delta D) = (3 xx10^(-5) xx 10^(-3))/(5 xx 10^(-2)) = 6 xx 10^(-7)m`
`= 6000Å`