BRAINCAKEWaves
Revision notes for Waves in Edexcel Physics (1PH0). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.
- Waves transfer energy and information, not matterA wave is a disturbance that travels through a medium, such as water, air or a solid.
- Evidence that the wave travels, not the mediumYou can see that a water wave does not carry the water with it.
- Frequency and wavelengthThe frequency of a wave is the number of waves that pass a point each second.
- Amplitude, period, wave velocity and wavefrontThe amplitude of a wave is the maximum displacement of a point on the wave from its rest position.
- Longitudinal and transverse wavesIn a transverse wave the particles of the medium, or the fields, vibrate at right angles to the direction of energy transfer.
- Wave speed equationsFor all waves, wave speed (v, in metres per second, m/s) is found from frequency (f, in hertz, Hz) and wavelength (λ, in metres, m): wave speed =…
- Measuring the speed of sound and of ripples on waterThe speed of any wave is found from the distance it travels divided by the time taken: v = x ÷ t.
- Calculating depth or distance from time and wave velocityMany instruments find a distance by timing a wave.
- Reflection, refraction, transmission and absorption at interfacesWhen a wave reaches the boundary between two materials, called an interface, four things can happen.
- Refraction at a boundaryRefraction happens when a wave crosses a boundary between two materials and its speed changes.
- How substances treat waves of different wavelengthsWhen a wave meets a substance it can be absorbed, transmitted, refracted or reflected, or a mixture of these.
- Converting between sound waves and vibrations in solidsSound in air is a longitudinal wave, a series of compressions and rarefactions.
- UltrasoundSound is a longitudinal wave of vibrating particles, so it needs a medium to travel through.
- InfrasoundHumans cannot hear sounds with a frequency below about 20 Hz.
- Uses of ultrasound and infrasoundSonar.
- Sound passing between mediaWhen a sound wave passes from one medium to another, such as from air into water, its frequency is unchanged.
- Core practical: measuring wave speed, frequency and wavelengthIn this practical you decide whether the equipment you have is suitable for measuring the speed, frequency and wavelength of a wave in a solid and…