Waves Flashcards
Define a Cycle
One complete vibration of a wave
Define displacement
How far a point has moved
From its undisturbed position
Define Amplitude
Maximum magnitude of displacement
From 0
Define period
Time taken per wave cycle
Seconds
Define frequency
Wave cycles per second
Hertz
Define phase
A measurement of the position of a certain point along the wave cycle
Define phase difference
Amount that one wave lags behind another
In degrees/radians or fraction of wavelength
Define reflection
Wave changes direction at a boundary
Define refraction
Wave enters different medium (of different n)
Changes speed and
Bends towards/away from the normal
Define a progressive wave
A wave that transmits energy from one place to another
Without transmitting matter
How is a stationary wave produced?
Two identical progressive waves (of same wavelength)
Travelling in opposite directions
Superimpose
What is the principle of superposition?
When two waves meet
Total displacement at any point = sum of individual displacements at that point
Define a longitudinal wave
Particle vibrations(energy transfer) parallel to direction of movement
Define a transverse wave
Particle vibrations(energy transfer) are perpendicular to direction of movement
What is coherence?
When 2 waves have the same frequency and constant phase difference
In a single slit interference pattern…
The subsidiary maxima are half the length of the central maxima
Define monochromatic light
Light of a single wavelength
Differences between Monochromatic and white light when passing through a slit?
Full spectra in subsidiary maxima in white light
Central white maxima
Wider maxima
How do sound waves transmit energy?
Vibrating source
Energy transfered to molecules in medium
Molecules collide .. Oscillations
Pressure waves transfer energy in direction of movement
How to prove a wave is transverse?
Polarisation
