Question

a biconvex lens of Glass having refractive index 1.47 is immersed in a liquid. it becomes invisible and behaves as a plane glass plate. refractive index of the liquid is:-
a. 1.47
b. 1.62
c. 1.33
d.1.51​

Answer 1

The refractive index of the liquid is:

a. 1.47

• As per the question, the biconvex lens of glass having refractive index 1.47 is immersed in a liquid and then behaves like a plane glass plate.

• This shows that the ray will pass undeviated through it.

• This is only possible when the medium's refractive index is the same as that of a biconvex lens.

• Thus, the refractive index of the liquid must be 1.47.