Question

The refractive index of the diamond is 2.42 . Explain this statement .

Answer 1

The strength of the medium by which it can bend the light when it travel through it is called the refractive index of that medium...

This can be Measured by the ratio of Velocity of light in Air or vaccume to the Velocity of light in Medium....

The symbol for refractive index is ' u ' Pronunce as myu..

u = velocity of light in air / Velocity of light in Medium

It has no Unit....as it is the ratio of velocities...

There is a phenomena called Refraction in which when light enter in a medium its velocity change or it bend....

The velocity of light is fastest in vaccum (free space) or little slow in air...approximately equal...

But when it enters different medium like glass , water , dimaond ...velocity of light decreases...
This means that Whenever we take a ratio of Velocity of light to velocity of light in any medium is always greater than 1...

i.e, The value of Refractive index u is always grater than 1...

The refractive index of diamond is 2.42...Lets understand what does this mean...

refractive index of diamond = 2.42

Let V1 = Velocity of light in air
V2=Velocity of light in diamond
u=Refractive index of Diamond i.e = 2.42

Now we have u = 2.42
V1 / V2 = 2.42
V1 = 2.42 x V2 ----(1)
From relation (1)..The velocity of light in vaccume is 2.42 faster than in Diamond...

This is actually a comparision of speed of light in vaccum with speed of light in other medium...which how fast is the speed of light when it travel from different medium....
Hope you get it....

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.