Chapter 4.4 - Waves Flashcards
Progressive wave
Transfers energy without transferring material and in the same direction
Displacement
Distance of a point from its rest position
Amplitude
Maximum magnitude of the displacement
Wavelength
The length of one full wave cycle
Period
Time taken for a whole cycle to complete
Frequency
Number of full cycles passing a point per second
Phase
A measurement of position of a certain point along a wave cycle
Phase difference
Difference in phase between two points
Equation for wave speed
v=fλ
How an oscilloscope works
y axis is voltage, x axis is time and it plots a wave
Transverse waves
Vibration is perpendicular to direction of motion
Longitudinal waves
Vibration is parallel to direction of motion
Intensity in terms of waves
The rate of flow of energy per unit area at right angles to the direction of travel
How intensity is related to amplitude
Intensity is proportional to amplitude squared
Polarisation
To restrict vibrations of a transverse wave to a single direction
How visible light can be polarised
Using a polarising filter
How microwaves can be polarised
Using a metal grille. When the plane of oscillation is parallel to that of the grille, all the of energy will be absorbed and no polarised light will pass through, although some will be emitted in random directions. Most of the light makes it through when the plane is perpendicular (seems counter intuitive)
Diffraction
When waves spread out when they go through a gap
When will maximum diffraction occur
When the gap width is equal to the wavelength
How a ripple tank works and can be used to view wave effects
Ripple tanks are shallow tanks of water, where an oscillating paddle generates horizontal waves. Objects can be placed in the tank to create barriers
How intensity of a polarised wave is related to angle
cos^2 of the angle
Main principle of reflection of waves
angle of incidence = angle of reflection (where they are measured from the normal)
What happens when light is shone through a single slit
You get a diffraction pattern