In the Young's experiment, the distance between slit and screen is doubled and the distance between the two slits is reduced to half. The fringe widht is

Options

A. `3 beta`
B. `2 beta`
C. `4 beta`
D. `6 beta`

Answer

A

Explanation

`D_(2)=2D_(1),d_(2)=(d_(1))/(2),beta_(2)-beta_(1)=?`
`betaprop(D)/(d)`
`:.(beta_(2))/(beta_(1))=(D_(2))/(D_(1))xx(d_(1))/(d_(2))`
`beta_(2)=(2D_(1))/(D_(1))xx(d_(1))/((d_(1))/(2))xxbeta_(2)=4beta_(1)`
`:.beta_(2)-beta_(1)=4beta_(1)-beta_(1)=3beta_(1)=3beta`