Question

Refractive index of glass is 1.5 and velocity of light in air is 3 * 10^8m/s. Then the time
taken to travel a distance of 4 × 10^8m in glass is: a)6s b) 4 s
c) 2s
d) Is
​

Answer 1

Answer:

Given,n  

g

​  

=1.5,n  

vacuum

​  

=1 and velocity of light in vacuum is 3×10  

8

.

Velocity of light in glass is :

n  

g

​  

 

v  

v

​  

×n  

v

​  

 

​  

 

=  

1.5

3×10  

8

×1

​  

 

=2×10  

8

.

Therefore, time taken by light in travelling 500m in glass is  

2×10  

8

 

500

​  

 

=2.5 μs

Explanation: