Question

The speed of light in a certain transparent material is 65.8% of the speed of light in vacuum. What is the index of refraction of the material?Can you identify the material?a.)crown glassb.)water c.)vacuumd.)diamonde.)air

Answer 1

ANSWER

• n = 1.52

,

• Crown glass

EXPLANATION

First, we have to look up the refractive indices of these substances:

• crown glass: 1.52

,

• water: 1.333

,

• vacuum: 1

,

• diamond: 1.417

,

• air: 1.0003

The speed of light in a medium with a refractive index n is given by,

$v=\frac{c}{n}$

Where c is the speed of light in vacuum.

In this problem, the speed of light in s certain material is 65.8% of the speed of light in vacuum, so we have,

$0.658c=\frac{c}{n}$

Solving for n,

$n=\frac{c}{0.658c}=\frac{1}{0.658}\approx1.52$

Hence, the refractive index of the material is 1.52, which means that the material is crown glass.