The basics concept that is emphasized for wave optics is the condition of constructive and destructive interference.
The condition for constructive interference is when two sources travel difference distances to the same location. The difference in the path lengths is mλ when m is 0, 1, 2, 3...
The condition for destructive interference is when two sources travel difference distances to the same location. The difference in the path lengths, is (m+1)λ when m is 0, 1, 2, 3...
This unit when over three different types of interferences. They each have described the path length difference with different relationships.
ΔL = mλ ...The generic condition for constructive interference
ΔL = (m+1/2)λ ...The generic condition for destructive interference
Where ΔL is the difference in path lengths.
Notice how these equations all fit a pattern |
Interference Type |
| Double slit |
| dsinθ = mλ (m=0, 1, 2,...) |
Constructive |
| dsinθ = (m+1/2)λ (m=0, 1, 2,...) |
Destructive |
| Single Slit |
| asinθ = mλ (m=0, 1, 2,...) |
Destructive |
| asinθ = (m+1/2)λ (m=0, 1, 2,...) |
Constructive |
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