A wave passes from one material into another. Its speed decreases and its frequency stays the same. What happens to the wavelength, and why?
It stays the same, because the frequency of the wave has not changed.
It decreases, because the wave speed is the frequency multiplied by the wavelength.
It increases, because the wave speed is the frequency divided by the wavelength.
It stays the same, because the wavelength depends only on the source of the wave.
40 exam-style questions on AQA GCSE Physics 6.1 Waves in air, fluids and solids, covering 6.1.1 Transverse and longitudinal waves, 6.1.2 Properties of waves, 6.1.3 Reflection of waves, 6.1.4 Sound waves (HT only), and 6.1.5 Waves for detection and exploration (HT only). Each one has a worked solution and a mark scheme showing where the marks go.