Water (with refractive index `=4//3`) in a tank is 18cm deep. Oil of refractive index `7//4` lies on water making a convex surface of radius of curvature `R=6cm` as shown. Consider oil to act as a thin lens. An object S is placed 24cm above water surface. The location of its image is at 'x' cm above the bottom of the tank. Then x is

Answer

2

Explanation

`(mu_(2))/(v)-(mu_(1))/(u)=(mu_(2)-mu_(1))/(R)`
`(7)/(4v)-(1)/(-24)=(7/4-1)/(6)`
`(7)/(4v)-(1)/(-24)-(1)/(24)=(2)/(24)=(1)/(12)`
` (7xx12)/(4)=V=21 cm`
`(21)/(OS)=(7//4)/(4//3) (21)/(OS)=(7)/(4)xx(3)/(4)`
`OS=16`
`therefore BS=2 cm`