A linear aperture whose width is `0.02cm` is placed immediately in front of a lens of focal length `60cm`. The aperture is illuminated normally by a parallel beam of wavelength `5xx10^-5cm`. The distance of the first dark band of the diffraction pattern from the centre of the screen is

Options

A. 0.15 cm
B. 0.10 cm
C. 0.25 cm
D. 0.20 cm

Answer

A

Explanation

Position of 1st minima
`y= (lambdaD)/(a)= ((5 xx 10^(-5))(60))/(0.02)= 0.15 cm`