A parallel beam of light of wavelength 600 nm is incident normally on a slit of width d. If the distance between the slits and the screen is 0.8 m and the distance of `2^(nd)` order maximum from the centre of the screen is 15 mm. The width of the slit is

Options

A. `40 mu m`
B. `80 mu m`
C. `160 mu m`
D. `200 mu m`

Answer

B

Explanation

Distance of `2^(nd)` order maximum from the centre of the screen
`x=(5)/(2)(D lambda)/(d)`
Here, `D=0.8m,x=15mm=15xx10^(-3)m`
`lambda=600nm=600xx10^(-9)m`
` :. d=(5)/(2).(D lambda)/(x)=(5)/(2)xx(0.8xx600xx10^(-9))/(15xx10^(-3))=80mu m`