An engineer uses ultrasound to test three bonded layers, A, B and C, of a pipe coating. The ultrasound travels from A into B and then into C. Its frequency remains constant. The speed of the ultrasound in B is three times its speed in A. Its speed in C is half its speed in B.
The wavelength in C is 0.72 mm.
What is the wavelength in A?
0.36 mm0.36\ \mathrm{mm}0.36 mm
1.08 mm1.08\ \mathrm{mm}1.08 mm
0.24 mm0.24\ \mathrm{mm}0.24 mm
0.48 mm0.48\ \mathrm{mm}0.48 mm
112 exam-style questions on Edexcel GCSE Physics 4.3 Sound, ultrasound and infrasound, covering 4.3.1 Sound waves, vibrations and the human ear, 4.3.2 Ultrasound and infrasound, 4.3.3 Uses of ultrasound and infrasound, and 4.3.4 Sound waves passing between media. Each one has a worked solution and a mark scheme showing where the marks go.