Question

P. 7Q 30
4. The refractive index of a medium'a with
respect to medium bis 2/3 and the refractive
index of medium b w.rt medium c is 4/3. Find
the refractive index of medium c wrt medium
a.​

Answer 1

Given :

Refractive index of medium A with respect to B = 2/3

Refractive index of medium B with respect to C = 4/3

To Find :

Refractive index of medium A with respect to C.

Solution :

■ Refractive index of a medium is defined as the factor by which speed of light reduces as compared to the speed of light in vacuum$.$

Moreover refractive index of medium 1 wrt medium 2 is given by, n₁₂ = n₁ / n₂

★ Refractive index of A wrt B :

→ n(AB) = n(A) / n(B)

→ 2/3 = n(A) / n(B) .......... (I)

★ Refractive index of B wrt C :

→ n(BC) = n(B) / n(C)

→ 4/3 = n(B) / n(C) ......... (II)

On multiplying both equations;

➠ n(A)/n(B) × n(B)/n(C) = 2/3 × 4/3

➠ n(A)/n(C) = 8/9

Hence, refractive index of medium A with respect to medium C is 8/9.