Question

The time taken by a monochromatic light to travel a certain distance in air is $9 \times {10}^{ - 6} s$The time taken by the light ray to travel the same distance in water of refractive index 4/3 isa) 12sb) 12μsc) (27/2)μ sd) (27/4)μ s

Answer 1

Answer:

Using the relation

v

2

v

1

=

μ

1

μ

2

where v

1

and v

2

are the respective velocity of light in air and water and μ

1

and μ

2

are the respective refractive index of air and water.

Given : μ

2

=

3

4

and μ

1

=1

Time taken by light to travel a distance x in air 9×10

−6

s and that in water be t.

⇒

t

x

9×10

−6

x

=

1

3

4

Or

9×10

−6

t

=

3

4

⇒t=12 μsec