Waves and the Particle Nature of Light Flashcards
What is a wave?
A periodic disturbance in a material or space which transfers energy
Frequency Definition
Number of waves passing a point per second
Amplitude Definition
Maximum displacement of a wave
Wavelength Definition
Distance covered by a full cycle of a wave
Time Period Definition
Time taken for one complete oscillation
Coherent Definition
Two waves with the same wavelength and frequency with a constant phase difference.
What is the frequency equation?
Frequency (Hz) = 1 / Time Period (s)
What is the wave speed equation?
Wave speed (ms^-1) = Frequency (Hz) x Wavelength (m)
What is the intensity equation?
Intensity (Wm^-2) = Power (W) / Area (m^-2)
What are longitudinal waves?
Oscillations parallel to the direction of energy transfer, made up of compressions and rarefractions that are transmitted through a medium (e.g. sound)
What is the speed of sound?
330 ms^-1
What is a transverse wave?
Oscillations perpendicular to the direction of energy transfer
What is the wavelength of visible light?
4 to 7 x 10^-7
What is the speed of light?
300000000 ms^-1
What is a standing wave?
Standing waves are created by the superposition of two progressive waves of equal frequency and amplitude moving in opposite directions causing energy to be stored.
What is a node?
A node is a point on a standing wave where destructive interference occurs as waves are anti - phase so it is a point of zero displacement.
What is an anti-node?
An anti-node is a point on a standing wave where constructive interference occurs as waves are in phase so it is a point of maximum displacement.
What is the speed of a transverse wave on a string equation?
Speed (ms^-1) = Square root of Tension (N) / mass per unit length (kgm)
What is superposition?
When two or more waves meet at a pint and there resultant displacements sum together
What is interference?
Outcome of a combination of waves through superposition
What is constructive interference?
In phase waves meet at a point and sum to create a amplitude of maximum displacement (antinode)
What is destructive interference?
When two waves which are anti phase meet and there resultant amplitude is zero (node)
What is meant by anti-phase?
When the phase difference is 180 degrees
What is meant by in phase?
When there is no phase difference between the two waves.