Question

if tha absolute refractive index of glass and water is 3.2 and 4.3 respectively then find tha ratio of speed of light on water and glass
​

Answer 1

Given : n

water

=

3

4

n

glass

=

2

3

v

glass

=2×10

8

m/s n

air

=1

Speed of light in a medium v

medium

=

n

c

where c and n are the speed of light in vacuum and refractive index of medium respectively.

(a) : v

glass

=

n

glass

c

∴ 2×10

8

=

(3/2)

c

⟹c=3×10

8

m/s

(b) : v

water

=

n

water

c

∴ v

water

=

(4/3)

3×10

8

=2.26×10

8

m/s