A fringe width in Young's experiment is 0.8 mm for a certain source when the screen is at a distance of 50 cm from the slits. If the distance of screen from the slits is increased to 200 cm, other things remaining same the new fringe width is

Options

A. 3.2 mm
B. 1.2 mm
C. 1 mm
D. 4 mm

Answer

A

Explanation

As fringe width `beta=(Dlamda)/d`
`(beta_(1))/(beta_(2))=(D_(1))/(D_(2))=0.8/(beta_(2))=50/200`
`beta_(2)=(0.8xx200)/50=3.2mm`