Light from a point source in air falls on a spherical glass surface. If `mu = 1.5`, and radius of curvature `= 20 cm`, the distance of light source from the glass surface is `100 cm` , at what position will the image be formed ? (NCERT Solved Example)

Options

A. `25 cm`
B. `50 cm`
C. `100 cm`
D. `200 cm`

Answer

C

Explanation

Here, `mu_(1) = 1, R = 20 cm, u = - 100 cm, mu_(2) = 1.5`
`:. (1)/(100) + (1.5)/(v) = (1.5 - 1)/(20) = 1/(40)`
or `(3)/(2v) = (1)/(40) - (1)/(1000)= (5-2)/(200) = (3)/(200) rArr v = 100 cm`
Hence, the image is formed a distance of 100 cm from the glass surface.