Waves - progressive and stationary Flashcards
What is a progressive wave?
A wave that transfers energy without transferring material
What is amplitude of a wave?
A waves maximum displacement from its equilibrium position (units are m)
What is frequency (f)?
The number of complete oscillations passing through a point per second (units are Hz)
What is wavelength?
The length of one whole oscillation or distance between successive peaks and troughs (units are m)
What is wave speed (c)
Distance travelled by wave per unit time (unit m/s)
What is the phase of the wave?
The position of a certain point on a wave cycle (units degrees, radians or fractions of a cycle)
What is phase difference?
How much a particle/wave lags behind another particle/wave (units are degrees, radians or fraction of a cycle)
What is the period of a wave?
Time taken for one full oscillation
When will waves be in phase?
If they are at the same point of the wave cycle
What are the properties of waves that are in phase?
Have the same:
- displacement
- velocity
- frequency
- wavelength
May not have the same amplitude.
Phase difference will be a multiple of 360 degrees or 2 pi radians.
When are waves completely out of phase (antiphase)?
Odd integer of half cycles apart e.g. 5 and a half cycles cycles apart where half cycle is 180 degrees or pi radians
Equation for wave speed?
Wave speed = frequency * wavelength
Equation for frequency?
Frequency = 1/period
What is a transverse wave?
Oscillation of particles (or fields) is at right angles to the direction of energy transfer
Examples of transverse waves?
All electromagnetic waves are transverse and have the speed 3*10^8 ms^-1 in a vacuum
Can be demonstrated by waves on a string when attached to a signal generator
