Question

what do you mean by that refractive index of diamond is 2.4?

Answer 1

the refractive index of diamond is 2.42. ... When we say refractive index of diamond is 2.42, it means light is travelling from rarer to denser medium, and speed of light in air (vacuum) is 2.42 times the speed of light in diamond.

Answer 2

Explanation:

Firstly ,

→ Refractive index :- It is defined as the speed of light in a first medium with respect to second medium.

°•° Refractive index = Speed of light in air(Vacuum )/ Speed of light in medium.

Here,

→ Rarer medium is Air .

And, The denser medium is diamond.

Because, light is travelling from rarer medium to denser medium .

▶ The refractive index of diamond is 2.42.

→ This statement means that When we say refractive index of diamond is 2.42, it means light is travelling from rarer to denser medium, and speed of light in air (vacuum) is 2.42 times the speed of light in diamond.

OR .

→ The speed of light in diamond is $\bf \frac{1}{2.42}$ times more than the speed of light in vacuum.