Question

When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts as a plane sheet of glass. This implies that the liquid must have refractive index 

(a) equal to that of glass 

(b) less than one 

(c) greater than that of glass 

(d) less than that of glass

Answer 1

Correct option  (a) equal to that of glass 

Explanation:

According to lens maker's formula

where μ_g, is the refractive index of the material of the lens and μ_L. is the refractive index of the liquid in which lens is dipped.

As the biconvex lens dipped in a liquid acts as a plane sheet of glass, therefore