Q.

A spherical interface lens of radius R separates two media of refractive indices 1 and 1.4 respectively as shown in the figure below. A point source is placed at a distance of 4R in front of spherical interface. The magnitude of the magnification of point source image is ______.          [2026]

1 1.66  
2 2.33  
3 2.66  
4 1.33  

Ans.

(1)

μ2v-μ1u=μ2-μ1R

1.4v-1-4R=1.4-1R⇒v=283R

m=μ1μ2vu=11.4×28R3×4R=74.2=1.66