Waves Flashcards
progressive wave definition
waves that transfer energy away from a source
transverse vs longitudinal waves
transverse travel perpendicular to direction of energy transfer, longitudinal parralel
wavelength deginition
Distance between two ADJACENT points on a progressive which are oscillating in phase
restoring force
a force which acts to bring a particle to it’s equilibrium position after it’s been displaced
amplitude definition
MAXIMUM displacement from the equilibrium point
displacement
is the direction and magnitude a particle has travelled from the equilibrium point
displacement vs amplitude
amplitude is the maximum distance, displacement doesn’t have to be
wavespeed equation
wavespeed = frequency * wavelength
frequency equation
frequncey = 1 / time period
true or false displacement-distance graphs are identical for transverse & longitudinal waves
true
what else happens wjen a wave refracts
partial reflection
what is the reflection of a sound wave
echo
polarised waves definition
waves that are restricted to oscillate in 1 plane (1), perpendicular to the direction of energy transfer
polarisation definition
the phenomenon in whoich oscillations of a transverse wave are limited to 1 plane
phase difference defintiion
difference between displacements of particles (1) on a wave/ different waves
In-phase
when particles oscillate in step reach their maximum positive displacement at the same time
anti-phase
when particles oscillate out of step; one reaches it’s maximum +ve displacement & the other particle reaches maximum -ve displacement
phase difference equation
distance between particles/wavelength
what is phase difference measured in?
radians/ degrees
how many radians & degrees is 1 cycle
1 cycle = 360 degrees = 2 radians
what are 2 point described as if they have a phase difference of 180 degrees (1 radian)
anti-phase
what are wavefronts
the peak of a water wave (i.e ripples)
how can wavelength change, but frequency stay the same after refraction
e.g wavelength decreases, but wavespeed decreases ‘at same rate’
definition of diffraction
the phenomenon in which waves spread out when passing through a gap or travel around a obstacle
true or false all EM waves included light can be diffracted
true
what changes when a wave diffracts? speed, wavelength, or frequency?
none of them
What impacts how much a wave diffracts
depends on the relative side of hre wavelength and the gap / obstacle
when is a wave diffracred the most
when the size of the gap/pbstacle is the same as the wavelength
name four properties that are the same for all ENM waves
- travel at same speed in vacuum: 300,000 km/s
- can be reflected, diffracted & refracted
- all are transverse waves
describe a wave that is in-phase
when party=icles osciliate IN STEP, i.e reach thier maximum positive displacement at the same time
equation to solve phase difference
phase difference = distance between 2 particles / wavelength * 360 degrees
waht can you find from displacememnt - distacne graph?
wavelength
waht can you find from displacememnt - time graph?
PERIOD of the wave; not it’s frequcney
what do displacement -time graphs and displacement -distance graphs both represent
amplitude of wave
how can light be polarised
use a polarising filter
reflect the light
what EM waves are polarised for real life uses
radio waves
what material can EM waves not pass through
metal
what are polarised waves called
plane-polarised wave
what is the symbol for unpolarised waves? vertically polarised? horizontally polarized?
search it up
what is the law of reflection
when waves are reflected, the angle of incidence = angle of reflection
when waves are reflected, …. changes …. don’t change
wavelength and frequency don’t change
when waves are refracted, …. changes …. don’t change
wavelength changes,
what is Snell’s law
sin i is directly proportional to sin r
how do you calculate refractive index?
n = speed of light in a vacuum/ speed of light in medium
when does toal internal reflection occur?
when angle of incidence is greater than the critical angle
when does refraction occur?
when the angle of incidence is smaller than the critical angle
What happens to the pattern when the width of the slit is reduced?
The intensities of all of the peaks decrease and the width of the pattern increases.
similarities between longitudinal and transverse wvaes
They both transfer energy from one place to another without any overall (net) movement of matter.
difference between oscillation vs waves
An oscillation describes the periodic motion of a particle about its mean position or equilibrium position,
whereas a wave refers to the motion of the energy outwards from the initial disturbance
what does sound wave speed depend on (2)
type of medium & temperature
should the angle be below, above or equal to the critical angle to be internally reflected when pass into different medium
above
should the angle be below, above or equal to the critical angle to be refracted and partially internal refelcted when pass into different medium
below
should the angle be below, above or equal to the critical angle to pass along boundary when pass into different medium
equal
