- Need help?
CAIE
7. Waves
7.1 Progressive waves
- describe what is meant by wave motion as illustrated by vibration in ropes, springs and ripple tanks
- understand and use the terms displacement, amplitude, phase difference, period, frequency, wavelength and speed
- understand the use of the time-base and y-gain of a cathode-ray oscilloscope (CRO) to determine frequency and amplitude
- derive, using the definitions of speed, frequency and wavelength, the wave equation v = f λ
- recall and use v = f λ
- understand that energy is transferred by a progressive wave
- recall and use intensity = power/area and intensity ∝ (amplitude) 2 for a progressive wave
7.2 Transverse and longitudinal waves
- compare transverse and longitudinal waves
- analyse and interpret graphical representations of transverse and longitudinal waves
7.3 Doppler effect for sound waves
- understand that when a source of sound waves moves relative to a stationary observer, the observed frequency is different from the source frequency (understanding of the Doppler effect for a stationary source and a moving observer is not required)
- use the expression f ο = fs v /(v ± vs ) for the observed frequency when a source of sound waves moves relative to a stationary observer
7.4 Electromagnetic spectrum
- state that all electromagnetic waves are transverse waves that travel with the same speed c in free space
- recall the approximate range of wavelengths in free space of the principal regions of the electromagnetic spectrum from radio waves to γ-rays
- recall that wavelengths in the range 400–700nm in free space are visible to the human eye
7.5 Polarisation
- understand that polarisation is a phenomenon associated with transverse waves
- recall and use Malus’s law (I = I0 cos2 θ ) to calculate the intensity of a plane polarised electromagnetic wave after transmission through a polarising filter or a series of polarising filters