H211 Waves Flashcards
Qhat happens in progressive waves?
In progressive waves, energy is propagated from one place to another in the direction of wave travel without bulk movement of medium.
Define wavefront.
A wavefront is an imaginary line that joins all the points of a wave that are at the same phase.
Define speed of a progressive wave.
The speed of a progressive wave is the speed at which energy is transferred.
What is the formula for wave speed?
v = wavelength x frequency
Define wavelength.
The wavelength of a wave is the minimum distance between two points with the same phase.
Define phase.
Phase is an angular measure of the fraction of a cycle completed by the oscillating mass.
Define phase difference.
Phase difference is the measure of how much an oscillation is out of step with another oscillation at the same instant in time.
Define transverse waves.
A transverse wave s ont where the oscillations are normal to the direction of energy propogation.
Define longitudinal wave.
A longitudinal wave is one where the oscillations are parallel to the direction of energy propogation.
Define intensity of a wave.
The intensity of a wave is the rate of energy flow per unit area that is perpendicular to the direction of wave propagation.
What is the formula for intensity?
I = Power/Area
What is the relationship between intensity and amplitude?
Intensity is directly proportional to the square of amplitude.
What is a polarised wave?
In a polarised wave, the oscillations are along one direction only, in a single plane that is normal to the direction of energy transfer of the wave.
What is Malus’ Law?
Intensity is directly proportional to cos^2 x
Define frequency
Number of crests passing a point per unit time
