In a young's double slit experiment the fringe width is $0.05\;mm$ when the distance of screen from slit is $75 \;cm$ . If the distance of screen from the slit is increased by $25 \;cm$ , the fringe width will be

Question

$(a)\;0.66\;mm \\ (b)\;0.066\;mm \\ (c)\;6.0\;mm \\ (d)\;60\;mm $