Unit 2 - Wave Properties Flashcards
When are two waves said to be coherent?
When they have the same speed, frequency, wavelength & have a constant phase relationship
What is the determining test for a wave?
Interference
When does constructive interference occur?
When two waves that are in phase meet
When does destructive interference occur?
When two waves that are exactly out of phase meet
What happens in constructive interference?
Two waves combine producing a larger wave
What happens in destructive interference?
Two waves meet & cancel each other out
Where is a maximum created?
At points of constructive interference
Where is a minimum created?
At points of destructive interference
What is path difference?
The difference in distance from one source to a point and the other source to a point
What is the path difference at a maximum?
Zero or a whole number of wavelengths
What is the path difference at a minimum?
A number of half wavelengths
What equation can be used to calculate path difference at a maximum?
Path difference = n X wavelength
What equation can be used to calculate path difference at a minimum?
Path difference = ( n + 1/2) X wavelength
What is a diffraction grating?
A piece of glass with very fine lines etched onto it
What is the grating equation?
m X wavelength = dsinx