## Saturday, 6 September 2014

### WAVE PROPERTIES PROBLEMS

WAVE PROPERTIES

Take the speed of light in free space to be 3x108 ms-1

1. (a) What is meant by the frequency of a wave?
(b) What is meant by the displacement of a wave?
(c) What is meant by the amplitude of a wave?
(d) What is meant by the wavelength of a wave?
(e) How are frequency, wavelength and velocity related to one another?
(f) How is the time period of a wave related to its frequency?

2. (a) State three wave phenomena that apply to both transverse and longitudinal waves.
(b) Name one wave phenomena that applies to only transverse waves
(c) Describe with the aid of a diagram the answer to part (b).

3. What is the difference between a transverse wave and a longitudinal wave?

4. This question is about electromagnetic waves travelling in free space:
(a) Find the frequency of a wave where the wavelength (l) = 1cm
(b) Find the wavelength of a wave with a frequency of 100 MHz
(c) Find the wavelength of a wave with a frequency of 300Hz

5. What is meant by the term diffraction?

6. What is meant by the term interference?

7. What are the conditions necessary for a static interference pattern to be produced?

8. What happens to the speed of a light wave as it enters a block of glass?

9. Which colour of light experiences the greater change in speed when entering glass?

10. Draw a diagram to show the effect of a plane water wave diffracting through an obstacle in a ripple tank.

11. What would be the effect on the pattern that you have drawn in number 11 if:
(a) the wavelength was increased
(b) the gap was increased in size using the initial wavelength.

12. Calculate the fringe width for a double slits interference pattern for yellow light (wavelength 600 nm) if the two slits are 0.5 mm apart are placed 1.5 m from the screen.

13. Describe the interference pattern produced if white light is used.

14. What is meant by:
(a) a travelling wave
(b) a standing wave

15. How can a standing wave be produced from two travelling waves?

16. Draw a diagram of a standing wave to explain what is meant by:
(a) a node
(b) an antinode

17. Draw diagrams to show:
(a) a transverse wave
(b) a longitudinal wave

18.How do the particles that carry the energy move in:
(a) a transverse wave
(b) a longitudinal wave

19. What is meant by the term path difference?

20. Using a sheet of graph paper draw the wave that is formed by the superposition of two standing waves, one of frequency f and amplitude A and the other of frequency 2f and amplitude A/2.

21. A stretched string is plucked at the centre and then lightly touched one quarter of the way from one end. Draw the result wave that is formed on the string.

22. What is meant by fibre optics?

23. Describe two use of fibre optics.

24. A beam of light of wavelength 600 nm hits a glass air interface at an angle of 40o. If the velocity of light in glass is 2x108 ms-1 find:
(a) The angle of refraction
(b) The wavelength of the light in the glass