In an interference experiment with a biprism, the distance of the slits from the screenn is increased by 25% annd the separation between the slits is halved. If X represents the original fringe width, the new fringe width will be

Options

A. `2.5X`
B. `1.5X`
C. `2X`
D. `4X`

Answer

A

Explanation

`D_(2)=1.25 D_(1) D_(2)=(d_(2))/(2), beta_(2)= b ? beta_(1)=x`
`b=(D)/(d)`
`:. (beta_(2))/(beta_(1))=(D_(2))/(D_(1))xx(d_(1))/(d_(2))`
`beta_(2)=(1.25 D_(1))/(D_(1))xx (d_(2) xx 2)/( d_(1)) xx beta_(1)`
`beta_(2)=2.5 beta_(1) = 2.5 X`