SSS 2: Light waves (II)

             Refraction of light waves

Refraction is the bending of a light ray as it crosses the boundary between two media of different densities thereby causing a change in its direction. 

where:

          i = angle of incidence 

          r = angle of refraction 

         N = normal 

As light ray moves from one medium to another, the speed and wavelength of light change but the frequency remains unchanged.

The speed of light can change when light travels from one medium to another of different refractive index(optical density)

where e= emergent angle 

                 Laws of refraction 

1. The incident ray, the refracted ray, and the normal at the point of incidence all lie on the same plane 

2. The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant for a given pair of media.

The second law is also known as Snell's law.

    Sin i  ÷ Sin r = n,   a constant for a given pair of media 

            n = Sin i   

                  Sin r