A beam of light of wavelength `600nm` from a distant source falls on a single slit `1mm` wide and the resulting diffraction pattern is observed on a screen `2m` away. The distance between the first dark fringes on either side of the central bright fringe is

Options

A. `2 . 4 m m `
B. 1 . 2 m m
C. 2 . 4 m m
D. 1 . 2 cm

Answer

A

Explanation

Width of central maxima in diffraction pattern is
`2 X = (2 D lambda)/(a) ` (where a is size of aperture)
`:. 2 X = ( 2 xx 2 xx 600 xx 10^(-9))/(10^(-3))`
`= 2 . 4 xx 10^(-3) m = 2 . 4 ` m m