11.2 Wave properties Flashcards
What is displacement?
The distance from the equilibrium position in a particular direction, so it can have either a positive or negative value.
- ( s )
- Units: metres
What is amplitude?
The maximum displacement from the equilibrium position (can be positive or negative).
- ( A )
- Units: metres
Define wavelength
The minimum distance between two points in phase on adjacent waves, for example, the distance from one peak to the next or from one compression to the next.
- ( λ )
- Units: metres
What is a period of oscillation?
The time taken for one oscillation or time taken for wave to move one whole wavelength past a given point.
- ( T )
- Units: seconds
Define frequency
The number of wavelengths passing a given point per unit time.
- ( f )
- Units: Hz
Define wavespeed
The distance travelled by the wave per unit time.
- ( v )
- m/s
What is the equation for wave speed?
v = f λ
What is the wave speed for a wave that has a frequency of 5.0Hz, each wave has a wavelength of 2.0 metres?
Each second there are 5 complete oscillations and if each wave has a wavelength of 2m, then the wave has travelled 10m in that time thus the speed is 10 m/s
What is the period of a wave if it has a frequency of 2.0Hz?
If the frequency is 2.0Hz then there are two complete wave cycles each second. Therefore the period for each wave must be 1/2.0 = 0.5
Define phase difference.
Phase difference describes the difference between the displacements of particles along a wave, or the difference between the displacements of particles on different waves. It is often measured in degrees or radians, with each complete cycle or wave representing 360° or 2π radians.
In what case is the phase difference zero?
If particles are oscillating perfectly in step with each other (they both reach their maximum positive displacement at the same time) then they are described as in phase.
In what case is the phase difference 360° or 2π radians?
If the two particles are separated by a distance of one whole wavelength.
In what case are particles in anti-phase?
If particles are oscillating completely out of step each other (one reaches its maximum positive displacement and the other reaches its maximum negative displacement at the same time)
