Retrieval Practice
Progressive Waves — AQA A-Level Physics
Q1. Define a progressive wave.
A wave that transfers energy from one point to another without transferring the medium itself.
Q2. Define the amplitude of a wave.
- The maximum displacement of a particle in the wave from its equilibrium position.
- Measured in metres.
Q3. Define the wavelength of a wave.
- The distance between points on successive oscillations that are in phase.
- Measured in metres.
Q4. State the relationship between frequency and period.
- f = 1/T.
- Frequency is the reciprocal of period.
Q5. State the wave equation.
v = f lambda, where v is wave speed (m/s), f is frequency (Hz), and lambda is wavelength (m).
Q6. What is the phase difference between two points that are in antiphase?
180 degrees or pi radians or half a wavelength.
Q7. Convert a phase difference of 1/4 wavelength into degrees and radians.
1/4 x 360 = 90 degrees. 1/4 x 2 pi = pi/2 radians.
Q8. State the relationship between intensity and amplitude.
Intensity is proportional to the square of amplitude: I is proportional to A squared.
Q9. A wave has a frequency of 50 Hz. What is its period?
T = 1/f = 1/50 = 0.02 s.
Q10. When using the wave equation, should you write c or v for wave speed?
- Use c only for the speed of light in a vacuum (\(3 \times 10^{8}\) m/s).
- For all other wave speeds, use v.