Question

Light travels through air at 300 million ms. On entering water, it slows down to 225 million ms. Calculate the refractive index of water.​

Answer 1

Answer:

Here, mediums 1 and 2 are air and water, respectively.

Refractive index of water= Speed of light in air / Speed of light in water

Therefore, = 300 million ms/225 million ms

=1.33

Which is your answer

Answer 2

Answer:

The refractive index of water is 1.33.

Explanation:

Refractive index is a measure of the speed of light in a medium to that in the air or free space. It is a dimensionless quantity. If c is the speed of light in a vacuum and v is the speed of light in a particular medium, then the refractive index of the medium is given by the equation:

n = c / v

We have c = 300 million = 300 × 10⁶ m/s

and v = 225 million = 225 × 10⁶ m/s

∴ Refractive index of water, n = (300 × 10⁶) / (225 × 10⁶)

                                              n = 1.33