In double slit experiment, the angular width of the fringes is `0.20^@` for the sodium light `(lambda=5890Å)`. In order to increase the angular width of the fringes by `10%`, the necessary change in the wavelength is

Options

A. increased of `589 Å`
B. decreases of `589 Å`
C. increases of `6479 Å`
D. 0

Answer

A

Explanation

The angular freingwdith is,
`theta=(lambda)/(d) and theta_(0)=(lambda_(0))/(d) :. (lambda_(0))/(lambda)=(theta_(0))/(theta)=(10)/(100)=0.1`
`:. lambda_(0)=0.1lambda= 0.1 xx5890=598 Å`