If the first minima in Young's double-slit experiment occurs directly in front of one of the slits (distance between slit and screen `D = 12 cm` and distance between slits `d = 5 cm)`, then the wavelength of the radiation used can be

Options

A. 2 cm
B. 4 cm
C. `(2)/(3)cm`
D. `(4)/(3)cm`

Answer

AC

Explanation

By Geometer, path difference at 0 for minima should be `(2n-1)(lamda)/(2)`
`thereforeS_(2)O-S_(1)O=(2n-1)(lamda)/(2)`
`impliessqrt(D^(2)+d^(2))-D=(2n-1)(lamda)/(2)`
`implies(13-12)cm=(2n-1)(lamda)/(2)`
for n=1,2,3 `lamda=2cm,(2)/(3)cm`