Flashcards
Coherence and Interference
Cards in this deck (14)
- 1When waves are coherent they are...The same type of wave with a constant frequency and wavelength
- 2Between coherent waves, there is a constant......Phase difference
- 3What do the lines of a wavefront represent?The peaks of waves
- 4If we superpose a peak and a peak (or a trough and a trough) what do we get?Constructive interference (x2 amplitude)
- 5If we superpose a peak and a trough what do we get?Destructive interference (0 amplitude)
- 6Lines of Maxima and lines of Minima on wavefront (in phase, but if in anti-phase then X and N would swap places): (X=Maxima , N = Minima)
- 7Lines of Maxima:Where both wavefronts intersect (2 peaks)
Constructive interference - 8Lines of Minima:On 1 line of one source wavefront (peak), but in middle of 2 lines on the other (trough)
Destructive interference - 9Diagram to illustrate path difference:
- 10What is the path difference for the diagram above?2 (as 8λ-6λ = 2λ)
- 11When path difference is a whole number (nλ where n is an integer) what occurs?Constructive interference
(This means they are in phase) - 12When the path difference (n+0.5)λ what occurs?Destructive interference
(This means they are in anti-phase) - 13Path difference diagram using wavefronts and lines of maxima and minima :
- 14How to find path difference from wavelength and phase difference:(Wavelength / 2pi) x phase difference (in radians)