12.3 +12.4 Young's double slit experiment, stationary waves Flashcards
what does mono-chromatic mean?
all the waves emmited are of the same frequeny (colour)
describe why young had this set up
- filter: monochromatic
- single slit : diffraction would produce a coherant wave, producing a stable interference pattern
what do the fringes suggest?
bright fringes:
* contructive interference
* light waves arrive in phase
dark:
* deconstructive interference
* light waves arrive in anti phase
what is the equation from young’s slit experiement?
what is a stationary wave?
a wave that oscillates in time but does not transfer any (net energy)
how are stationary waves formed?
two progressive waves of same frequency propagate in opposite directions and superpose
only certain frequnecies will produce stationary waves (harmonic)
what is the amplitude of a stationary wave for a single point?
- constant at all times time
what is a node?
a point of zero displacement
distnace between 2 adjacent nodes =half λ
what is an anti node?
a point of maximum displacement
what is the phase difference between 2 adjacent nodes/ anti nodes ?
0
what is the phase difference between either side of a node ?
π (180 degrees)
what is the phase difference between all points between adjacent nodes?
0- they are all inphase, as they all reach maximum displacement together
do stationary waves transfer energy?
yes, but not tot heir surroundings
how are nodes and anti nodes created in a stationary wave?
between two progressive waves (same frequnecy ) travelling in opposite directions:
* destructive interference, (180 phase difference) = node
* constructive interefence,(0 phase diference) = anti node
what is the difference between the definition of ‘wavelength’ for the two different waves?
- progressive wave: distance between 2 adjacent points oscillating in phase
- stationary wave: twice distance between adjacent nodes = wavelength of 2 progressive waves (OG) that made the stationary