In Young's experiment inteference bands are produced on the screen placed at `1.5m` from the slits `0.15mm` apart and illuminated by light of wavelength `6000 Å`. If the scren is now taken away from the slit by 50 cm the change in the fringe width will be

Answer

2

Explanation

`D_(2) - D_(1) = 50 cm , D_(1) = 1.5m = 150 cm`
`lambda = 6000 overset(@)Delta = 600xx10^(-8) cm, d = 0.15mm`
Change in fringe width `Delta beta = beta_(2) - beta_(1)`
`Delta beta = (D_(2) - D_(1))(lambda)/(d) = (50xx6000xx10^(-8))/(0.15xx10^(-1))`
`Delta beta = (20xx10^(-4))/(10^(-3)) = 2xx10^(-1)cm = 2mm Delta beta = 2mm`