Edexcel GCSE Physics: Waves

Waves can be classified as either transverse or longitudinal.

Describe and explain the difference between a transverse wave and a longitudinal wave. In your answer you should refer to the direction of the oscillations relative to the direction of energy transfer, give a named example of each, and explain why a sound wave cannot travel through a vacuum but an electromagnetic wave can. (6 marks)

A student used a ripple tank to investigate water waves. They used a stopwatch and a ruler to record, for several different settings of the wave generator, the frequency of the waves and the wavelength measured on the screen.

Frequency / Hz	Wavelength / m
4.0	0.075
6.0	0.050
8.0	0.0375
10.0	0.030

(a) Using a row from the table, calculate the speed of the water waves. Use $v = f\lambda$v=fλ. Show your working and give the unit. (3 marks)

(b) State the relationship between frequency and wavelength shown by the data. (1 mark)

A sound wave travelling through air has a frequency of 170 Hz. The speed of sound in air is 340 m/s.

(a) Calculate the wavelength of the sound wave. Use $v = f\lambda$v=fλ. Show your working and give the unit. (2 marks)

(b) State what happens to the frequency of the sound wave if it passes from air into water (where it travels faster). (1 mark)

A wave has a period of 0.004 s.

(a) Calculate the frequency of the wave. Use $f = \dfrac{1}{T}$f=T1​. Show your working and give the unit. (2 marks)

(b) State what is meant by the period of a wave. (1 mark)

A ray of light travels from air into a glass block and is refracted.

Explain why the ray of light changes direction as it passes from air into the glass. (2 marks)

The amplitude is one of the basic properties used to describe a wave.

State what is meant by the amplitude of a wave. (1 mark)