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AS · Practice questions · Progressive waves

Speed, frequency, wavelength.

Six original Cambridge-style questions on the wave equation, phase, intensity and reading a CRO.

Original questions All questions on this page are original work, written in the Cambridge AS & A Level style. They are not from past papers. They test the same concepts and skills the syllabus rewards.
Keep these straight

One equation links them.

01
Analysis
[2 marks]

Define the amplitude and the wavelength of a wave.

  • Amplitude is the maximum displacement from the equilibrium position ✓
  • Wavelength is the distance for one complete cycle of the wave ✓
02
Analysis
[2 marks]

A wave has a frequency of 25 Hz and a wavelength of 0.40 m. Find its speed.

  • v = fλ = 25 × 0.40 ✓
  • v = 10 m s⁻¹ ✓
03
Analysis
[3 marks]

A radio station broadcasts at 100 MHz. Taking the speed of radio waves as 3.0 × 10⁸ m s⁻¹, find the wavelength.

  • λ = v / f = (3.0 × 10⁸) / (100 × 10⁶) ✓
  • λ = 3.0 m ✓
04
Analysis
[2 marks]

Two points on a wave have a phase difference of 180°. How far apart are they, as a fraction of a wavelength?

  • 180° is half a cycle ✓
  • So the points are half a wavelength (λ/2) apart ✓
05
Analysis
[3 marks]

On a CRO the time-base is 5.0 ms per division and one complete cycle occupies 4.0 divisions. Find the frequency of the signal.

  • Period = 4.0 × 5.0 ms = 20 ms = 0.020 s ✓
  • f = 1 / T = 1 / 0.020 = 50 Hz ✓
06
Analysis
[2 marks]

The amplitude of a wave is tripled with no other change. State the effect on its intensity.

  • Intensity is proportional to amplitude squared ✓
  • So it becomes 3² = 9 times as great ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.