Describing waves

3 marks · Normal

A source vibrates and produces 15 waves in 3 seconds.

(a)

Calculate the frequency of the wave.

[2 marks]

(b)

State the unit of frequency.

[1 mark]

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(a) 5 Hz

(b) hertz/Hz

Common mistakes: Dividing time by the number of waves instead of dividing waves by time

Show mark scheme and worked solution

Marking points

M1 (a) · 1 mark · Uses the correct formula: frequency = number of waves / time. (follow-through)

A1 (a) · 1 mark · Correct calculation: 15 / 3 = 5 (Hz). (follow-through)

B1 (b) · 1 mark · States the correct unit: hertz/Hz.

Worked solution

a) Frequency = number of waves / time

f = 5 Hz

b) The unit of frequency is hertz (Hz).