Optics
Constructive Interference Condition
Constructive interference occurs when the path difference between two waves is an integer multiple of the wavelength, resulting in maximum amplitude.
Variables
Δm
Path difference
munitless
Order number (0, 1, 2, ...)
Allowed values: 0 or more, whole number
λm
Wavelength
Allowed values: greater than 0
Your notes
0/5000
Check value
Round inputs run through this page's calculator. Use it to test your own working or a rearranged form. It is a test case, not a real-world example.
- m = 2 (Order number (0, 1, 2, ...))
- λ = 3 m (Wavelength)
Result: Δ = 6 m
Other optics formulas with the same quantities
- Fringe Spacing (Wave Optics) shares Wavelength
- Single-Slit Diffraction (Wave Optics) shares Wavelength
- Diffraction Grating (Wave Optics) shares Wavelength
- Resolving Power of Grating (Wave Optics) shares Wavelength
- Rayleigh Criterion (Resolution) shares Wavelength
Where this formula is listed
- Optics formulas, under Wave Optics.
- In the optics list it comes after Optical Path Length and before Brewster's Angle.
- Optics formula sheet, one of 34 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Constructive Interference Condition formula?
Constructive Interference Condition is written Δ = mλ. Constructive interference occurs when the path difference between two waves is an integer multiple of the wavelength, resulting in maximum amplitude. It belongs to Optics, under Wave Optics.
What are the units in Δ = mλ?
In SI units, Δ is path difference, measured in m; m is order number (0, 1, 2, ...) (dimensionless); λ is wavelength, measured in m.