C4 Light waves

1 a) In the 17th century there were two conflicting theories about the nature of light. Huygens proposed one of these theories and Newton supported the other. Briefly outline these TWO theories.

Newton Huygens b) Young provided experimental evidence that supported one of the theories in a). Which one did it support? c) Einstein used one of the theories in a) to explain the observations of experiments in which light was interacting with matter. Which one was it? b) Light is usually thought of as travelling in straight lines because diffraction is not normally observed. State why this is so and state ONE observation that supports this. c) Draw two diagrams to show the diffraction of waves through a narrow gap and a wide gap. d) What can be said about the wavelength of a wave before and after it passes through a gap? e) Under what conditions do waves show the most diffraction? b) The diagram below shows an object O in front of a plane mirror. Two rays of light R1 and R 2 are shown. Complete the path taken by the two rays and locate the image O.

2 a) Explain what is meant by the term ‘diffraction’.

3 a) State the laws of reflection.

4 a) Explain what is meant by the ‘refraction’ of light.