CBSE Class 10 Science 2016 Term II Outside Delhi Set 3

Question : 4 of 11

Marks: +1, -0

The refractive indices of glass and water with respect to air are

3 \/ 2

and

4 \/ 3

respectively. If speed of light in glass is

2 × 10^8 {\m} \/ {\ s}

, find the speed of light in water.

Solution:

Refractive index of a medium

=\;{\;\text " Speed of light in air "\;}/{\;\text " Speed of light in the medium "\;}

For glass,

\;{3}/{2}=\;{\;\text " Speed of light in air "\;}/{2 × 10^8}

Speed of light in air

=\;{3}/{2} × 2 × 10^8=3 × 10^8 {\m} \/ {\ s}

.
For water,

\;{4}/{3}=\;{\;\text " Speed of light in air "\;}/{\;\text " Speed of light in water "\;}

Speed of light in water

=3 × 10^8 × \;{3}/{4}=2.25 × 10^8 {\m} \/ {\ s}

Go to Question:

Prev Question

Next Question