2005 Question 7
A student used a laser, as shown, to demonstrate that light is a wave motion.
(i) Name the two phenomena that occur when the light passes through the pair of narrow slits.
(ii) A pattern is formed on the screen. Explain how the pattern is formed.
(iii)What is the effect on the pattern when the wavelength of the light is increased?
(iv) What is the effect on the pattern when the distance between the slits is
increased?
(v) Describe an experiment to demonstrate that sound is also a wave motion.
(vi) Sound travels as longitudinal waves while light travels as transverse waves.
Explain the difference between longitudinal and transverse waves.
(vii) Describe an experiment to demonstrate that light waves are transverse
waves.
2005 Question 12 (c)
(i) The frequency of a stretched string depends on its length.
Give two other factors that affect the frequency of a stretched string.
(ii) The diagram shows a guitar string stretched between supports 0.65
m apart.
The string is vibrating at its first harmonic. The speed of sound in
the string is 500 m s–1. What is the frequency of vibration of the string?
(iii)Draw a diagram of the string when it vibrates at its second harmonic.
(iv) What is the frequency of the second harmonic?
