Unit 4 - Waves & Sound Flashcards
(18 cards)
Wave
The transfer of energy in the form of a disturbance. Mechanical waves travel through a material (as a medium), while electromagnetic waves do not require a medium.
Cycle
One full oscillation of one complete sequence
Period
Time it takes to complete on cycle, one oscillation or one complete sequence of the action.
period = #second / cycle
Frequency
With which the object oscillates describes ow many cycles occur each second.
frequency = # cycles / second
Amplitude
Maximum displacement of disturbance from equilibrium point
Transverse wave
The motion of the medium is perpendicular to the direction of the motion of the wave.
Crest
Highest point on transverse wave
Trough
Lowest point on transverse wave
Longitudinal waves
The motion of the medium is parallel to the direction of the motion of the wave.
Compressions and rarefractions
Nodes
Points of the wave that neither rise nor fall
Antinodes
Midway between these nodal points, are points of the wave that rise or fall by the greatest amount.
Wavefront
Shape of a continuous crest or trough
Infrasonic
Below 20 Hz
Ultrasonic
Above 20000 Hz
The Doppler Effect
The Doppler Effect describes the effect of a moving source of a moving receiver on emitted waves. As applied to waves, this results in a change in the pitch of a sound depending on the movement of the source of the sound or movement of the person hearing the sound.
Power
Rate of energy transfer
Intensity
Intensity = power / area
Sound intensity
Defined as the average rate of energy flow per unit area across a surface that is perpendicular to the direction that the sound is traveling
