11 Waves Flashcards
What is a progressive wave
an oscillation that travels through matter (or in some cases a vacuum), transferring energy from one place to another, but not transferring any matter
Two examples of progressive waves
Transverse and longitudinal
What is a transverse wave
With a transverse wave the direction of oscillation of a wave is perpendicular to the direction of the motion of the wave
Give 4 examples of transverse waves
.Waves on the surface of water
. Any Electromagnetic wave
. Waves on stretched strings
. S- waves produced in earthquakes
What are peaks and troughs and on what type of wave do they apply to
Apply to transverse waves-
Peaks- where the oscillating particles are at a maximum displacement from their equilibrium position (max positive displacement)
Trough- where the oscillating particles are at a maximum displacement from their equilibrium position (max negative displacement)
What is a longitudinal wave
With a longitudinal wave the direction of oscillation of a wave is parallel to the direction of motion of the wave
Give 2 examples of longitudinal waves
. Sound waves
. P- waves produced in earthquakes
What type of wave produces compressions and rarefactions
Longitudinal waves
Def:Displacement of a wave
Distance from the equilibrium position in a particular direction;a vector, so it can have either a positive or negative value
Def:Amplitude
Maximum displacement from the equilibrium position (can be positive or negative)
Def:Wavelength
Minimum distance between two points in phase on adjacent waves, for example, the distance from peak to the next or from one compression to the next.
Def:Period of oscillation
The time taken for one oscillation or time taken for wave to move one whole wavelength past a given point
Def:Frequency
The number of wavelengths passing a given point per unit time
Def:Wave speed
The distance travelled by the wave per unit time
The wave equation
v=f λ
Frequency equation
f=1/T
Wave profile
A graph showing the displacement of the particles in the wave against the distance along the wave (displacement-distance graphs)
What can the wave profile be used to determine
The wavelength and amplitude of both types of wave
Phase difference
Phase difference describes the difference between the displacements of particles along a wave, or the difference between the displacements of particles in different waves
Antiphase
Particles are oscillating completely out of step with each other (one reaches its maximum positive displacement as the other reachers its maximum negative displacement). Phase difference of 180°, or π radians
What can a graph of displacement against time be used to determine
Period T and amplitude of both types of waves (longitudinal and transverse)
Reflection
Reflection occurs when a wave changes direction at a boundary between two different media, remaining in the original medium
Law of reflection
The angle of incidence is equal to the angle of reflection
What does not change during reflection
The wavelength and frequency
Refraction
Occurs when a wave changes direction as it changes speed when it passes from one medium to another.
Partial reflection
When a wave refracts there is always some reflection off the surface
What will cause the wave refracting towards the normal/ away from the normal
If the wave slows down it will refract towards the normal, if it speeds up it refracts away from the normal.
What properties change during refraction
Refraction has an effect on the wavelength of the wave, but not its frequency.
Refraction- What happens to the wavelength and frequency when a wave slows down
Wavelength decreases and frequency remains unchanged
