Waves
Science, Physics. Usually met in years 9 to 11.
Use wave speed, frequency, wavelength and time period, and work out distance from an echo.
What you practise
- Wave speed = frequency × wavelength
- Time period
- Echo calculations
Finishes with the distance to a wall from an echo. Practice moves up a level when a round goes well and down when it does not.
Sample questions
Each sample comes with the method and the reason every wrong option is wrong. Real practice rounds are ten questions at your level.
Sample question, level 2 of 5
A wave travels at 50 m/s with a wavelength of 2 m. What is its frequency?
- 25 Hz
- 100 Hz
- 16.667 Hz
- 48 Hz
- 0.04 Hz
Show the answer and method
Answer: A, 25 Hz
The method: Frequency = wave speed ÷ wavelength = 50 ÷ 2 = 25 Hz.
Why the other options are wrong:
- B, 100 Hz: The speed was multiplied by the wavelength. Frequency = speed ÷ wavelength.
- C, 16.667 Hz: Close, but check the division.
- D, 48 Hz: The wavelength was subtracted from the speed.
- E, 0.04 Hz: The division is upside down. Frequency = speed ÷ wavelength.
Sample question, level 4 of 5
A wave has a frequency of 20 Hz. What is its time period?
- 20 s
- 200 s
- 0.025 s
- 0.05 s
- 2 s
Show the answer and method
Answer: D, 0.05 s
The method: Time period = 1 ÷ frequency = 1 ÷ 20 = 0.05 s.
Why the other options are wrong:
- A, 20 s: The frequency was given as the period. Period = 1 ÷ frequency.
- B, 200 s: The decimal point is one place out.
- C, 0.025 s: The frequency was doubled first.
- E, 2 s: The frequency was divided by 10. Period = 1 ÷ frequency.
See where this fits: GCSE science with AQA and Key Stage 3.
Related topics: Density, Forces, Electricity, Energy.
