Light from a point source in air falls on a spherical glass surface (n = 1.5 and radius of curvature = 20 cm ). The distance of the light source from the glass surface is 100 cm. At what position the image is formed ?

Explanation

`(n_(2))/(v) - (n_(1))/(u) = (n_(2) - n_(1))/(R ) `
u = - 100 cm , v = ? , R = + 20 cm , `n_(1) = 1 and n_(2) = 1.5`.
We then have `(1.5)/(u) + (1)/(100) = (0.5)/(20) or v = + 100 ` cm
The image is at a distance of 100 cm from the glass surface , towards right.