In a double slit interference experiment, the fringe width obtained with a light of wavelength 5900 A was 1.2 mm for parallel narrow slits placed 2 mm apart. In this arrangement if the slit separation is increased by one-and-half times the previous value, then the fringe width is

Options

A. 0.9 mm
B. 0.8 mm
C. 1.8 mm
D. 1.6 mm

Answer

b

Explanation

According to young's double slit interference experiment,
`implies beta=(lambdaD)/d`
`therefore beta_(1)/beta_(2)=d_(2)/d_(1)`
`implies1.2/beta_(2)=1.5`
`beta_(2)=1.2/1.5`
`therefore beta_(2)= 0.8 mm`