Question

Please send in explanation​

Answer 1

Required Answer:

Let's understand what is absolute Refractive index!

When light travels from vacuum to another medium, then the refractive index is said to be absolute Refractive index.

Absolute Refractive index can be defined as the ratio of Speed of light in vacuum to the speed of light in given medium.

Or,

$\underline{\boxed{\sf\large \mu=\dfrac{Speed\: of\: light\:in\:Vacuum}{Speed\:of\: light\:in\: medium}}}$

Here, $\mu$ refers to absolute Refractive index.

Hence option (b) is correct.

Note that absolute Refractive index can't be less than 1 as the medium to which light is traveling can't be rarer to vacuum. Speed of light is maximum in vacuum.

Additional information:

• What is the speed of light in vacuum?

Speed of light in vacuum is 3×10⁸m/s. Light travels fastest in vacuum.

• What is the need of refractive index?

Refractive index is used to calculate how much the given medium optically denser is. Or in simple words, it is used to find optical density of a medium.