Question

The velocity of light in air is 3×10⁸ m/s . Calculate the velocity of light in a Plexiglas of refractive index 1.51 .

Answer 1

Answer:

According to Snell's Law:  

sin r

sin i

​

=  

n  

1

​

 

n  

2

​

 

​

=  

v  

2

​

 

v  

1

​

 

​

 and Refractive Index for air is ≈1

Substituting,  

1

1.5

​

=  

v  

2

​

 

3×10  

8

 

​

 

Therefore, v  

2

​

=  

1.5

3×10  

8

 

​

=2×10  

8

 m/s

Explanation: