Longer wavelengths (red light, ~700nm) produce wider diffraction patterns, while shorter wavelengths (violet, ~400nm) create narrower patterns. The minima positions shift proportionally with λ.
Narrower slits cause more spreading of light. When slit width b ≈ λ, diffraction is maximum. For b >> λ, the pattern approaches geometric optics with minimal spreading.
The central bright fringe is twice as wide as secondary maxima and contains ~84% of total transmitted light energy. Secondary maxima decrease rapidly in intensity.
Dark fringes occur when: b sin θ = nλ (n = ±1, ±2, ±3...)
Path difference equals integral multiple of wavelength causing destructive interference.
Bright fringes occur approximately when: b sin θ ≈ (n+½)λ
Secondary maxima are not exactly at half-integer values due to interference envelope.
Fraunhofer Diffraction occurs when parallel light (plane waves) passes through an aperture and the diffraction pattern is observed at infinite distance (or focal plane of a lens).
For a slit of width b, the intensity I at angle θ is:
sin(β)
β
Where β = (πb sin θ)/λ.
Minima occur at: b sin θ = nλ (n = ±1, ±2...)
For a circular hole of diameter D, the intensity is:
2J₁(x)
x
Where x = (πD sin θ)/λ and J₁ is the Bessel function of first kind.
First Minimum (Airy Disk edge): sin θ ≈ 1.22 λ/D
Choose wavelength (380-780 nm). The slider changes color to show the selected visible light. Red light = 700nm, Violet = 400nm.
Set slit width (500-5000 nm). Try b ≈ λ for maximum diffraction. Choose single-slit or circular aperture type.
Move observation angle (0°-90°). Use Maxima/Minima dropdowns to jump to specific diffraction orders instantly.
Check relative intensity readout. Switch between pattern view and intensity graph to understand the diffraction envelope.