A single narrow slit of width 0.1 mm, is illuminated with a parallel beam of light of wavelength `600xx10^(-9)`m . An diffraction fringe is formed on a screen 40 cm away from the slit. At what distance, will the third minimum band be formed from the central maximum band?

Explanation

We know, if the distance between n th minimum and central maximum be `x_(n)`, then
`x_(n) = (nDlambda)/(a)` [ here, n = 3 , a = 0.1 mm = 0.01 cm,
D = 40 cm and `lambda = 600 xx 10^(-9) m = 600 xx 10^(-7)` cm]
`therefore " "x_(3) = (3xx 40 xx 600xx10^(-7))/(0.01) = 12 xx 6 xx 10^(-2) = `0.72 cm