Refraction and Total Internal Reflection


(a) Tick the appropriate boxes in the table below to indicate how the wavelength, frequency and speed of light are affected when a ray of light travels from air into glass.

  wavelength frequency speed
stay the same      

[2 marks]

(b) The diagram belowshows a right-angled glass prism in contact with a transparent substance on one of the faces. One of the other angles of the prism is θ.

(i) Ray A enters perpendicularly to one face of the prism.

It is partially refracted and partially reflected at the interface between the glass and the transparent substance.

The angle of refraction is 65.0º. The ray eventually leaves at an angle α to the surface of the transparent substance.

Determine the angle α.

[2 marks]

(ii) Determine the angle θ

[2 marks]

(c) This new diagram shows another ray entering the prism:

(i) Identify the effect that takes place at X

[1 mark]

(ii) Explain, with a diagram, how the effect that occurs at X is used to transmit information along an optic fibre.

[3 marks]

(Total 10 marks)