In young's double slit experiment the distance between two sources is`0.1//pimm`.the distance of the screen from the source is `25cm`.wavelength of light used is `5000Å`.Then the angular position of the first dark fringe is-

Options

A. `0.10^(@)`
B. `0.15^(@)`
C. `0.30^(@)`
D. `0.45^(@)`

Explanation

The angular position
`theta =(beta)/(D)=(lambda)/(d) (therefore beta=(lambdaD)/(d))`
The first dark frigue will be at half the fringe width from the mid point of central maximum.thsu the angular position of first dark fringe will be -
`alpha=(theta)/(2)=(1)/(2)[(lambda)/(d)] alpha=(1)/(2)[(5000xxpi)/(.1xx10^(-3))xx10^(-10)](180)/(pi)`
`alpha=0.45^(@)`