The width of a single slit if the first minimum is observed at an angle `2^(@)` with a light of wavelength 6980 `overset(@)(A)` :

Options

A. 0.2 mm
B. `2 times 10^(-5)mm`
C. `2 times 10^(5)mm`
D. 2 mm

Answer

B

Explanation

The angular distance `(theta)` is given by
`" "theta=lambda/d`
`" "theta=2^(@)=pi/180 times 2, lambda=6980 overset(@)(A)`
`" "=6980 times 10^(-10)m`
`rArr" "d=lambda/theta=(6980 times 10^(-10) times 180)/(3.14 times 2)`
`" "1.89 times 10^(-5)mm`
`rArr" "d=2 times 10^(-5)mm`