Question

· The refractive indices of water and glass are 4/3 and
3/2 respectively. Find the speed of light in each.
(Similar 2005)​

Answer 1

Answer:

Absolute Refractive Index of a medium = Speed of light in vacuum/Speed of light in the medium

Speed of light in glass = 2 x 108 m/s

Speed of Light in Vacuum = (3/2) x 2 x 108 m/s = 3 x 108 m/s

Speed of light in water = (3 x 108 m/s)/(4/3)

                                        = 2.25 x 108 m/s

hope it helps :)

Answer 2

Given :

➾ Refractive index of water = 4/3

➾ Refractive index of glass = 3/2

To Find :

➨ Speed of light in each medium.

Concept :

➠ Refractive index of a medium is defined as the ratio of speed of light in vacuum to the speed of light in medium..

➠ It is an unitless as well as dimensionless quantity.

Mathematically,

✭ n = c / v

where,

➛ c denotes speed of light in vacuum

➛ v denotes speed of light in medium

➛ n denotes refractive index of medium

Calculation :

◈ Speed of light in water :

⇒ n = c / v

⇒ 4/3 = 3×10$^8$ / v

⇒ v = 2.25 × 10$^8$ m/s

◈ Speed of light in glass :

⇒ n' = c / v'

⇒ 3/2 = 3×10$^8$ / v'

⇒ v' = 2 × 10$^8$ m/s