The speed of light in air is 3.0 x 10^8 m/s. the speed of light in particular glass is 2.3 x 10^8 m/s. use the information to determine the angle of refraction of light which travels from the glass into air, if the angle of incidence on the glass/air boundary is 25° . draw a diagram.

33.61°

Explanation:

Refractive index is equal to velocity of the light 'c' in empty space divided by the velocity 'v' in the substance.

Or ,

n = c/v.

v is the velocity in the medium  (2.3 × 10⁸ m/s)

c is the speed of light in air = 3.0 × 10⁸ m/s

So,  

n = 3.0 × 10⁸ /  2.3 × 10⁸

n = 1.31

Using Snell's law as:

Where,  

 is the angle of incidence  ( 25.0° )

is the angle of refraction  ( ? )

is the refractive index of the refraction medium  (air, n=1)

is the refractive index of the incidence medium (glass, n=1.31)

Hence,  

Angle of refraction = = 33.61°

a and b sometimes have a positive value