In an experiment, light passing through two slits separated by a distance of 0.3 mm is projected on to a screen placed at 1 m from the plane of slits. It is observed that the distance between the central fringe and the adjacent bright fringe is 1.9 mm. The wavelength of light in nm is

Options

A. 450
B. 495
C. 530
D. 570

Answer

D

Explanation

Distance between central height fringe and next bright fringe is width of one dark fringe `beta` So,
`beta = (lamda D)/(d)`
` rArr 1.9 xx 10^(-3) = (lamda xx 1)/(0.3 xx 10^(-3) )`
`rArr lamda = 57 xx 10^(-8) m `
` = 570 xx 10^(-9) m = 570 nm`