Question

A spherical surface of radius 30cm separates two transparent media A and B with refractive indices 1.33 and 1.48 respectively. The medium A is on the convex side of the surface. Where should a point object be placed in medium A so that the paraxial rays become parallel after refraction at the surface ?

Answer 1

For par-axial rays become parallel after refraction ... so Image is formed at infinity

v=∞

μ1=1.33

u=?

μ2=1.48

R= 30cm

From the formula:

μ2/v - μ1/ u= μ2-μ1/R

=1.48 /∞  - 1.33/u  = 1.48-1.33/30

- 1.33/u- 0.15/30

u= - 266.0cm

Object should be placed at a distance of 266cm from surface on side A

Answer 2

Answer is explained below:-:-:-:--:-:-:-:-:-

For par-axial rays become parallel after refraction ... so Image is formed at infinity


v=∞

μ1=1.33


u=?


μ2=1.48


R= 30cm


From the formula:


μ2/v - μ1/ u= μ2-μ1/R


=1.48 /∞  - 1.33/u  = 1.48-1.33/30


- 1.33/u- 0.15/30


u= - 266.0cm


So,the object should be placed at a distance of 266cm from surface on side A