4.7 Superposition And Interference Flashcards
What is the principle of superposition?
When two waves of the same kind meet the resultant displacement is the sum of the individual displacements.
What happens when waves meet exactly crest to crest?
CONSTRUCTIVE interference occurs and the wave has double the amplitude of the individual waves.
What happens when waves meet crest to trough?
DESTRUCTIVE interference occurs when the wave has zero amplitude since the amplitudes have cancelled out.
What determines whether we have constructive or destructive interference?
On the difference in path length to that point from each source.
What is the difference in distances called?
Path difference.
When does constructive interference occur in regards to path difference?
When the path difference divided by the wavelength is a whole integer.
When does destructive interference occur in regards to path difference?
When the path difference divided by the wavelength is a half integer.
When are two wave sources coherent?
When their waves are exactly in step with one another.
What happens when light is diffracted through slit?
The waves superpose at a screen far away.
What does the intensity pattern shown from when the waves are diffracted through the slits?
Equally spaced maxima with equal intensities.
What do the maxima and minima of the intensity pattern depend on?
Path difference from the two slits.
What formula gives the separation of the two consecutive minima>
s = lambaD/d
where D is the distance to the screen
and d is the separation of the slits.
