# Waves – CIE AS Level Physics 9702

Contents:-

• Progressive waves
1. describe what is meant by wave motion as illustrated by vibration in ropes, springs and ripple tanks
2. understand and use the terms displacement, amplitude, phase difference, period, frequency, wavelength and speed
3. deduce, from the definitions of speed, frequency and wavelength, the wave equation $$v = f\lambda$$
4. recall and use the equation $$v = f\lambda$$
5. understand that energy is transferred by a progressive wave
6. recall and use the relationship intensity $$\alpha (amplitude)^2$$
• Transverse and longitudinal waves
1. compare transverse and longitudinal waves
2. analyse and interpret graphical representations of transverse and longitudinal waves
• Determination of frequency and wavelength of sound waves
1. determine the frequency of sound using a calibrated cathode-ray oscilloscope (c.r.o.)
2. determine the wavelength of sound using stationary waves
• Doppler effect
1. understand that when a source of waves moves relative to a stationary observer, there is a change in observed frequency
2. use the expression $$f_o = \frac{f_s v}{(v \pm v_s)}$$ for the observed frequency when a source of sound waves moves relative to a stationary observer
3. appreciate that Doppler shift is observed with all waves, including sound and light
• Electromagnetic spectrum
1. state that all electromagnetic waves travel with the same speed in free space and recall the orders of magnitude of the wavelengths of the principal radiations from radio waves to γ-rays

Video (1:55:37 mins)