WaPNoL 1 Flashcards
Amplitude
Maximum displacement from the equilibrium position.
Frequencey
Number of waves passing a point per second (or number of wave oscillations per second).
Period
Time for one complete wave oscillation. Period = 1/frequency (T = 1/f)
Wavelength
Distance between two consecutive points that are in phase (e.g. successive peaks).
Wave Equation
Wave speed (ms-1) = frequency (Hz) × wavelength (m) v = fλ
Phase
The fraction of a cycle one oscillation lags (or leads) another, often expressed as an angle.(phase difference): “In phase” means phase difference = 0°, “In anti-phase” means phase difference = 180 degrees
Wavefront
A wavefront is a line on which all the points are in phase (e.g. All peaks of a wave).
Transverse wave
The particles oscillate at right-angles to the direction of energy transfer (propagation). e.g. light.
Longitudinal wave
The particles oscillate backwards and forwards in the direction of energy transfer (propagation). e.g. sound.
Speed of light
Speed of light in a vacuum, c = 3 ×10^8 ms-1. (Note: Speed of light in air = 3 × 10^8 ms-1) Note: For any electromagnetic wave in a vacuum, the wave equation becomes c = fλ
Interference
The combination of two or more waves of the same type.
Coherence
Sources are coherent if they maintain a fixed phase-relationship
Principle of Superposition
“The resultant displacement of 2 or more waves at a point is equal to the VECTOR sum of their individual displacements at that point.”
Maxima
Waves meet with 0° phase difference, resulting in constructive superposition occurs producing a point/region of maximum amplitude.
Minima
Waves meet with 180° phase difference, resulting in destructive superposition occurs producing a point/region of minimum amplitude.