Electrons, waves, and photons: Waves 1 Flashcards
what is a progressive wave
a progressive wave is an oscillation that travels through matter and only transfers energy
what is a transverse wave
a wave on which the oscillations are perpendicular to the direction of energy transfer
what is a longitudinal wave
a wave in which the direction of oscillation is parallel to the direction of energy transfer
define displacement
displacement is the distance from the equilibrium position in a particular direction; it is a vector so can have either have a positive or negative value
define amplitude
maximum displacement from the equilibrium position
define wavelength
the minimum distance between two points in phase on adjacent waves
define the period of oscilation
the time taken for one oscillation or time taken for a wavelength to move one whole wavelength past a given point
define frequency
the number of wavelengths passing a given point per unit time (measured in Hz)
define wave speed
the distance travelled by the wave per unit time
what is the wave equation
V=fλ
how is frequency determined
f=1/T where T is the time period
define phase difference
the difference in displacements along a wavemeasured in degrees or radians
if two waves are in antiphase, what is the phase difference
180 degrees
what is the law of reflection
the angle of incidence is equal to the angle of reflection
does wavelength and frequency change when a wave is reflected
No
what is refraction
when a wave changes direction due to changing medium
what is diffraction
when an wave passes through a gap with similar size to its wavelength, they spread out
what is polarisation
when waves are only able to oscillate in only one direction on plane due to passing through a plane polariser or the method of emission
how is intensity defined
intenisty = radiant power per unit surface area
what is intensity proportional to and what is the relationship
intensity ∝ amplitude^2
what is an electromagnetic wave
a wave that is an oscillating pair of electric and magnetic fields travelling at the speed of light.
what is teh typical wavelenth of radio waves
meters
what is the typical wavelength of microwaves
cms
what is the typical wavelength of red light
700nm
what is the typical wavelenth of violet light
400nm
what is the approximate wavelength for X=rays
10^-10m
what is the approximate wavelength of gamma radiation
10^-12m
define refractive index
the ratio between the speed of light in a vacum compared to the relative speed of light in the material
what is snells law
nsinθ(1)=nsinθ(2)
