question_answer

A parallel narrow-beam of light is falling normally on a glass sphere. It will come to a focus

A)  Inside the sphere (except at its centre)

B)  On the surface of the sphere

C)  Outside the sphere

D)  Exactly at the centre of the sphere

Correct Answer: C

Solution :

Consider a parallel beam of light falling normally on a glass sphere. One of the ray passes undeviated through centre C as shown, other ray AB follows the path ABDI and forms image I, outside the sphere. \[{{N}_{1}}\] and \[{{N}_{2}}\] are normal to ^the spherical surfaces.