GCSE Questions - Waves![]() Q14. Here is some apparatus that can be used to investigate the waves in a stretched string.The frequency of the signal generator is adjusted so that a wave is seen - as shown in the diagram. At this frequency the string vibrates between the two positions shown in the diagram. (a) The wavelength of the wave shown in the diagram was measured as 80 cm. What piece of apparatus would have been suitable for measuring this wavelength? A metre rule or tape measure
[1 mark] (b) Write down the equation which links frequency, wavelength and wave speed. wave speed = frequency x wavelength v = fλ [1 mark] (c) The string vibrates at 55 Hz. Calculate the wave speed of the wave. Use the data given in the diagram. 80 cm = 0.8 m v = fλ v = 55 × 0.8 v = 44 m/s [3 marks] (d) The frequency of the signal generator is increased. This makes the wavelength of the wave change. The wave speed stays the same. Describe how the apparatus could be adjusted to show one complete wave without reducing the frequency. You could move the (wooden) bridge OR You could change the mass/weight on the string [2 marks] (e) A student wants to investigate how the speed of a wave on a stretched string depends on the tension in the string. The student uses the apparatus in the diagram above. Describe a method the student could use for this investigation.
- the examiner looks for relevant points - but also for a logical sequence... It is not just a 'tick fest' - but a marker does look to see how many relevant points you have made, then considers how you have strung them together to put your answer into a 'level'
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[4 marks] (Total 11 marks) |
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