Waves
4 marks · EasyA student investigates water waves in a ripple tank and observes the behaviour of a ray of light travelling from air into glass.
Describe what is meant by the amplitude and wavelength of a wave.
State what happens to the speed of a ray of light as it passes from air into glass.
Give one unit, other than the metre, used for measuring waves.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Amplitude: the maximum displacement from the equilibrium position. Wavelength: the distance between two corresponding points on adjacent waves (e.g., crest to crest).
(b) It slows down.
(c) Hertz (Hz), second (s), or metre/second (m/s)
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Amplitude described as the maximum displacement from equilibrium position.
B1 (a) · 1 mark · Wavelength described as the distance between two identical points on adjacent waves.
B1 (b) · 1 mark · Correctly states that light slows down when entering glass from air.
B1 (c) · 1 mark · Gives a correct unit (hertz, second, or metre/second).
Worked solution
a) The amplitude of a wave is the maximum distance a particle moves from its normal/rest position. The wavelength is the distance from one crest to the next crest (or between two identical points on neighbouring waves).
b) When light goes from air into glass, it slows down.
c) Possible units include hertz (Hz), second (s), or metre/second (m/s).