Resolving Power of Grating

R = \frac{\lambda}{\Delta\lambda} = mN

The ability of a grating to distinguish between two closely spaced wavelengths.

Variables

Resolving power

Allowed values: 0 or more

unitless

Wavelength

Allowed values: greater than 0

Δλ

Minimum resolvable wavelength difference

Allowed values: greater than 0

Order number

Allowed values: 0 or more, whole number

unitless

Number of slits

Allowed values: greater than 0, whole number

unitless

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)
N = 3 (Number of slits)

Result: R = 6

Other optics formulas with the same quantities

Double-Slit Interference (Wave Optics) shares Order number, Wavelength
Fringe Spacing (Wave Optics) shares Wavelength
Single-Slit Diffraction (Wave Optics) shares Wavelength
Thin Film Interference (Wave Optics) shares Order number
Constructive Interference Condition (Wave Optics) shares Wavelength
Rayleigh Criterion (Resolution) shares Wavelength

Where this formula is listed

Optics formulas, under Wave Optics, alongside Optical Path Length.
In the optics list it comes after Diffraction Grating and before Thin Film Interference.
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 Resolving Power of Grating formula?

Resolving Power of Grating is written R = λ/Δλ = mN. The ability of a grating to distinguish between two closely spaced wavelengths. It belongs to Optics, under Wave Optics.

What are the units in R = λ/Δλ = mN?

In SI units, R is resolving power (dimensionless); λ is wavelength, measured in m; Δλ is minimum resolvable wavelength difference, measured in m; m is order number (dimensionless); N is number of slits (dimensionless).