Question

Case study: Mirage in deserts

To a distant observer, the light appears to be coming from somewhere below the ground. The observer naturally assumes that light is being reflected from the ground, say, by a pool of water near the tall object. Such inverted images of distant tall objects cause an optical illusion to the observer. This phenomenon is called mirage. This type of mirage is especially common in hot deserts. Based on the above facts, answer the following question :

In an optical fibre, if n₁ and n₂ are the refractive indices of the core and cladding, then which among the following, would be a correct equation? 

Options

• n₁ < n₂

• n₁ = n₂ 

• n₁ << n₂

• n₁ > n₂ 

Answer 1

n₁ > n₂ 

Explanation -
The refractive index of the core should be greater than the refractive index of the cladding.