A piezoelectric crystal under the water in a glass tank produces sound with a frequency of 5.0 × 105 Hz. The sound travels through the water and into a glass wall.
| Material | Speed of sound in m/s\text{m/s}m/s |
|---|---|
| water | 1500 |
| glass | 5000 |
Use the equations
v=fλv=f\lambdav=fλ
T=1fT=\dfrac{1}{f}T=f1
Three possible values for the wavelength of the sound in the water are shown.
| Value | Wavelength in m\text{m}m |
|---|---|
| J | 3.0 × 10-4 |
| K | 3.0 × 10-3 |
| L | 3.0 × 10-2 |
Give the correct value. Justify your answer using v=fλv=f\lambdav=fλ.
The wavelength of the sound in the glass is 0.010 m.
Compare the factor by which the speed changes with the factor by which the wavelength changes when the sound enters the glass.
A student predicts that the period of the sound will be smaller in the glass because the sound travels faster in the glass.
Explain whether this prediction is correct.
State the name given to sound with a frequency of 5.0 × 105 Hz.
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.