Assertion (A): Propagation of light through an optical fibre is due to total internal reflection taking place at the core-clad interface. Reason (R): Refractive index of the material of the core of the optical fibre is greater than that of air.

Options

A. Both (A) and (R) are true and (R) is the correct explanation of (A)
B. Both (A) and (R) are true but (R) is not the correct explanation of (A)
C. (A) is true but (R) is false
D. (A) is false but (R) is true

Answer

B

Explanation

Optical fibre depends upon the principle of total internal reflection as the refractive index of the material of the core of the optical fibre is greater than that of air.