Physical Optics Flashcards
L
distance from slit to screen
d
slit spacing
Diffraction
bending of a wave due to a barrier or opening
What affects the bending?
size of opening/obstacle compared with wavelengths of the wave
Opening > wavelength
Waves move with little diffraction, creates a large shadow region
Opening similar to wavelength
very pronounced diffraction, wavefronts form a circular pattern with no shadow regions
The smaller the opening
the more significant the diffraction
Shadow region
regions with no wave activity
Huygen’s principle
- Every oscillator in a wave creates spherical wavelets that propagate outwards.
- The wavefront created by these oscillators is due to the combined interference of the wavelets
Constructive interference
identical wave crests is added together to create a single larger wave
Effects of constructive interference
- water waves increase in height
- sound becomes louder
- light becomes brighter
Destructive interference
When a wave crest meets a wave through, these waves will be canceled entirely
Effects of destructive interference
- absence of wave activity
- water becomes flat
- sound becomes quiet
- darkness instead of brightness
Monochromatic light
light composed of only one wavelength
When lines of constructive interference hit the screen
bright bands of light can be seen
Regions in between bright bands of light are dark
caused by destructive interference
Maximums and minimums are numbered:
starting with central maximum, m = 0
Maximums
whole numbers (m = 0, 1, 2, etc.)
Minimums
halves (m = 0.5, 1.5, 2.5)
Formula
x = mλL/d
d sin Θ = nλ
