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

Options

A. 2.4cm
B. 2.4mm
C. 1.2mm
D. 1.2cm

Answer

B

Explanation

The central maximum is twice as wide as any other secondary maximum or minimum distance between first two minimas
`therefore`  ` (beta=(2Dlambda))/(d)` 
=`(2xx2xx600xx10^(-9))/(1xx10^(-3))=2400xx10^(-6)m`=2.4mm