T4 - Waves Flashcards
Amplitude (A) - wave
Maximum displacement of the medium from the equilibrium position
Amplitude (A) - SHM
Maximum displacement from the equilibrium position
Simple harmonic motion (SHM)
an oscillation where the force (and acceleration) is proportional to displacement from the equilibrium position but is in the opposite direction
analyser
a device that can detect polarised light
antinode
position of maximum displacement
Brewster’s law
when light reflects off a surface it will be 100% polarised in the plane of the surface if the angle between the reflected and refracted rays is 90 degrees
coherent
wave sources that have a fixed phase relationship
compression
part of a longitudinal wave where the particles are closest together
constructive interference
occurs when two wave meet in phase to give the maximum displacement
critical angle (θc)
angle of incidence above which total internal reflection may occur
destructive interference
curse when two waves meet out of phase to give zero displacement
diffraction
spreading out of eaves past an obstacle or through a gap
displacement (X) - SHM
instantaneous distance from the equilibrium position in a specific direction
displacement (X) - wave
instantaneous distance the medium has moved from the equilibrium position in a specific direction
electromagnetic wave
do not require a medium so can travel through a vacuum
frequency (f) - SHM
number of oscillations per second
frequency (f) - wave
number of oscillation of the medium per second
fundamental frequency (fo)
the lowest frequency standing waves that can be formed a pipe or a string
intensity (I)
power per unite area received by an observer
isochronous oscillation
an oscillation with a constant time period
longitudinal wave
the particles of the medium oscillate parallel to the direction of energy transfer
Malus’ law
I = Io cos^2 θ
mechanical waves
requires a medium through which to travel
node
position of fire displacement
optically active substance
substance that rotates the plane of polarised light as the light passes through it
path difference
difference in distance travelled by two different waves, given in terms of wavelength
period (T) - SHM
time for one oscillation
period (T) - waves
time for one complete oscillation of the medium (or for a complete wave to pass a given point )
polarised light
light in which the electric field vector is oscillating on one plane only
rarefaction
part of a longitudinal wave where the particles are furthest apart
ray
shows the direction of energy transfer of a wave
refraction
the chance in speed of a wave that occurs when it travels into a different medium
refractive index (n)
a measure of how fast a wave travels in medium
retiring force - SHM
a force that is always directed towards the equilibrium position
Snell’s law
n = sin i / sin r
standing wave
a wave formed when a wave is reflected and the reflected wave interferes with the forward moving wave
superposition
a resultant wave formed by the addition of the displacement of individual aves when the interfere
total internal reflection
occurs when a wave is travelling into a less dense medium and when the angle of incidence at the boundary is greater that the critical angle
transverse waves
the particles of the medium oscillate perpendicular to the direction of energy transfer
wave
a movement of energy through a medium
wave speed (c)
distance travelled per unit time by the energy of wave
wavefront
Lin connecting points along a ave that are in phase
wavelength (λ)
shortest distance along a wave between two points that are in phase
