What is a wave?
A transfer of energy from one place to another without transferring matter.
What are the two main types of waves?
Transverse waves
Longitudinal waves
In a transverse wave, how do the oscillations move relative to the direction of energy transfer?
The oscillations are perpendicular (at right angles) to the direction of energy transfer.
In a longitudinal wave, how do the oscillations move relative to the direction of energy transfer?
The oscillations are parallel to the direction of energy transfer.
Give two examples of transverse waves.
Light waves
Water waves
Give two examples of longitudinal waves.
Sound waves
Seismic P-waves
What are compressions and rarefactions?
Compressions are regions where particles are close together.
Rarefactions are regions where particles are spread apart.
What are the main features of a transverse wave?
Amplitude
Wavelength
Frequency
Wave speed
What is the amplitude of a wave?
The maximum displacement of a point on the wave from its rest position.
What is the wavelength of a wave?
The distance between two corresponding points on consecutive waves (e.g. crest to crest).
What is the frequency of a wave?
The number of waves that pass a point per second.
Measured in hertz (Hz).
What is the time period of a wave?
The time taken for one complete wave to pass a point.
T = 1/f
What is the wave speed equation?
v=f×λ
Where:
v = wave speed (m/s)
f = frequency (Hz)
λ = wavelength (m)
What happens when a wave hits a surface?
It can be reflected, absorbed, or transmitted.
What is reflection?
When a wave bounces off a surface.
What is the law of reflection?
The angle of incidence = angle of reflection.
What is refraction?
The change in direction of a wave as it passes from one medium to another, caused by a change in wave speed.
What happens to the wavelength and speed of a wave when it enters a denser medium?
The wave slows down and the wavelength decreases.
What happens to the frequency of a wave when it enters a different medium?
The frequency stays the same.
What is diffraction?
The spreading out of waves as they pass through a gap or around an obstacle.
What is the normal line in reflection and refraction?
An imaginary line at 90° to the surface where the wave hits.
What is the difference between specular and diffuse reflection?
Specular reflection: from a smooth surface, waves reflect in a single direction.
Diffuse reflection: from a rough surface, waves reflect in many directions.
How can waves be used to find the speed of sound in air?
Measure the time between sound being made and heard at a known distance, then use
v = d/t
.
What equipment can be used to measure the speed of sound in a lab?
Microphones connected to an oscilloscope
Measure time delay between signals
