## Book: HC Verma - Concepts of Physics Part 1

### Chapter: 18. Geometrical Optics

#### Subject: Physics - Class 11th

##### Q. No. 38 of Exercises

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38
##### A spherical surface of radius 30 cm 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?

Spherical surface of Radius r= 30cm

Refractive indexes of two mediums are:

Medium A=

Medium B =

The medium A is on the convex side of the surface.

We know that;

Paraxial rays become parallel after refraction and the image is formed at infinity.

Therefore, image distance = v=

By using lens equation;

The object is placed at the distance of 266.0 cm from the convex surface on side A.

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