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

a.,c

Explanation

Path difference `= sqrt(D^(2) + d^(2)) - D = 1m`
Also,
`[sqrt(D^(2) + d^(2)) - D] = (2n - 1) (lambda)/(2)`
`lambda = (2(1))/(2n - 1)`
For `n = 1, 2, 3`,….
`lambda = 2 cm, (2)/(3) , (2)/(5) cm`,…