Question

Light passes from material A, which has an index of refraction of 4/3, into a material B, which has an index of refraction of 5/4. Find the ratio of the speed of light in the material B to the speed of light in material A.

Answer 1

Given,

Light passes from material A, which has an index of refraction of 4/3 into material B, which has an index of refraction of 5/4.

To find: Find the ratio of the speed of light in material B to the speed of light in material A.

Solution:

The refractive index is inversely proportional to the speed of the light in the material.

`\begin{gathered} (n_A)/(n_B)=(v_B)/(v_A) \\ ((4)/(3))/((5)/(4))=(v_B)/(v_A) \\ (v_(B))/(v_(A))=(16)/(15) \end{gathered}`

Thus, the ratio of the speed of light in the material B to the speed of light in material A is

`(v_B)/(v_A)=(16)/(15)`