An acoustic experiment is set up to study how sound waves behave when they pass through air regions of different temperatures. Figure 1 and Figure 2 show planar sound wavefronts propagating from a region of cold air into a region of warm air. The speed of sound is greater in warm air than in cold air.
Explain why refraction (a change in the direction of propagation) occurs at the boundary in Figure 1 as the sound waves travel from the cold air into the warm air.
Explain why the wavefronts in Figure 2 do not refract (change direction) when they cross the boundary, even though their speed changes.
Waves in air, fluids and solids Questions
Practise AQA GCSE Physics Waves in air, fluids and solids with exam-style questions for Foundation and Higher tier. 45 questions covering Transverse and longitudinal waves, Properties of waves, Reflection of waves (physics only), Sound waves (physics only) (HT only), and Waves for detection and exploration (physics only) (HT only), matched to the AQA GCSE Physics (8463) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.