Question Constellation Sign up for free AQA · GCSE · Physics · Higher
Wavelength of a Seismic Wave
An S-wave has a frequency of 3.6 Hz. The S-wave has a speed of 4.5 km/s. Use the Physics Equations Sheet.
Calculate the wavelength of this S-wave.
Write your answer first. You can study the marking guidance whenever you need it.
Study the marking See what earns credit and compare it with a full-mark answer.
Marking points
- 1 Converts 4.5 km/s to 4500 m/s and substitutes into v = fλ.
- 2 Rearranges correctly for wavelength.
- 3 Gives 1250 m or 1300 m from a correctly converted speed.
Full-mark answer
4.5 km/s = 4500 m/s. Using v = fλ, λ = v/f = 4500 ÷ 3.6 = 1250 m.
Why this answer loses marks
Divides the unconverted wave speed by the frequency.
The speed must first be converted into metres per second for a wavelength expressed in metres.