Waves Flashcards
Define superposition
where 2 waves overlap and a single combined wave is produced
What is the principle of superposition?
when 2 waves meet at a point, the resultant displacement at that point is equal to the sum of the individual displacements
Define destructive interference
when two waves meet and are in antiphase - the resultant wave has a smaller amplitude
Define constructive interference
when two waves meet and are in phase - the resultant wave has a larger amplitude
Define coherence
waves that are in phase and have the same frequency
what is an interference pattern?
shows patterns of destructive and constructive interference
define path difference
the difference in distance travelled by two coherent waves from their source
define monochromatic light
light that only emits one frequency
describe Young’s double slit theory
- he placed a filter in front of a light source to create monochromatic light
- the light passed through the slit and diffracted
- when a double slit was added, the light passed through both and formed an interference patterns - creating a maxima and a minima
- proved that light was formed of waves, not particles
describe how a stationary wave is formed
two progressive waves with the same wavelength and frequency interfere when in opposite directions
define node
points with 0 amplitude - progressive waves are in antiphase
define antinode
points with maximum amplitude - progressive waves are in phase
how is a stationary wave different from a progressive wave?
- it doesn’t transfer energy
- points have a different amplitude
- has nodes and antinodes
what is the relationship between the wavelength of the progressive waves (which form a stationary wave) and the distance between 2 nodes of the stationary wave
the separation between 2 adjacent nodes is half the wavelength of original progressive wave - wavelength/2
e.g. distance between 2 nodes = wavelength/2
relationship between length of fixed string and wavelength of progressive waves
(at fundamental mode of vibration)
wavelength = 2L
L is length of fixed string
what is fundamental frequency?
the lowest frequency of a stationary wave
what is the relationship between the number of antinodes on a stationary wave and wavelength of a progressive wave
wavelength = 2/n x L
n - number of antinodes
L - length of fixed string
what is the relationship between the number of antinodes on a stationary wave and frequency of a stationary wave
f = nf0
f0 - fundamental frequency
what are the conditions required for a stationary wave to form in a column of air with a closed end?
node at open end, antinode at closed end
what are the conditions required for a stationary wave to form in a column of air in an open tube?
antinodes at both ends
what is the link between length of a tube with a closed end and the wavelength of a stationary wave vibrating at its fundamental frequency?
L = 1/4 wavelength
