H212 Superposition Flashcards
Define Principle of Superposition
The Principle of Superposition states that when two or more waves meet at a point, the resultant displacement is sum of the displacement of each wave.
Define diffraction.
Diffraction is the spreading of a wave when it passes through a slit or past an edge of an obstacle.
What is the formula for single slit diffraction?
sin x = wavelength/slit width
What does the Rayleigh Criterion state?
The Rayleigh Criterion states that the limit for which 2 sources of light can be just distinguished is when the first minimum of the diffraction pattern of one source coincides with the central maximum of the diffraction pattern of the other source.
To solve Rayleigh Criterion questions what formula do you use?
Distance between two sources/r = x = wavelength/slit width (s/r = wavelength/b)
What are the conditions required for an interference pattern of alternating maxima and minima to be formed by two sources of waves?
- waves of the same type meet
- waves from sources have constant phase difference
- waves are transversed they are either unpolarised or polarised in the same plane
- for good contrast waves from sources should reach screen with the same amplitude.
What is the formula for double slit diffraction?
Fringe separation = wavelength(distance from double slits to screen)/slit separation
What is the formula for diffraction grating?
seperation between slits (sin x) = order of diffraction (wavelength)
How to find separation between slits?
d = unit length/N (eg 10^-3/6000)
How is a stationary wave formed?
A stationary wave is formed when two waves of the same type, same amplitude, same frequency, wavelength and speed travelling in opposite directions towards each other meet to superpose across a length.
What is the fundamental mode/frequency?
It is the mode of oscillation that has the lowest possible frequency of the standing wave.
What is the overtone?
It is the next possible mode of higher frequency from the fundamental mode.
