Light of wavelength `lambda=5000Å` falls normally on a narrow slit. A screen is placed at a distance of `1m` from the slit and perpendicular to the direction of light. The first minima of the diffraction pattern is situated at `5mm` from the centre of central maximum. The width of the slit is

Options

A. 0.1 mm
B. 1.0 mm
C. 0.5 mm
D. 0.2 mm

Answer

A

Explanation

Position of nth minima
`x_(n)= (nlambdaD)/(a)`
`implies 5 xx 10^(-3) = (1 xx 5000 xx 10^(-10) xx 1)/(a)`
`implies a= 10^(-4)m= 0.1 mm`