1Which of these has the same dimensions as wavelength?
Wavelength and mean free path both have the dimensions [L].
Oscillations and wavesClass 11, Waves
Dimensional formula of Wavelength
[L]
The distance between two successive crests. It has the dimension of length.
How to get the dimensional formula of wavelength
- Start from the definition: wavelength = length.
- Put in the dimension of each part: [L].
- Add the powers of each base quantity: [L].
Quantities with the dimensions [L]
- Length
- Displacement
- Radius of gyration
- Mean free path
- Amplitude
- Focal length
- Fringe width
- de Broglie wavelength
- Bohr radius
Equal dimensions do not make them the same quantity. Compare wavelength with the others in the full grid.
Three questions on wavelength
2What is the SI unit of wavelength?
The SI unit of wavelength is the metre (m).
3Which one has different dimensions from the others?
Wave number is [L⁻¹]. The other three are all [L].
An equation that uses wavelength
Equation checker
Matching dimensions are necessary, not sufficient. A check cannot see pure numbers such as 1/2 or 2π, so a consistent equation can still be wrong.
Read as
λ = h / (m v)lambda[L]=h/mv[L]Dimensionally consistentEvery term is [L]
v = velocity
Wavelength: quick answers
What is the dimensional formula of wavelength?
The dimensional formula of wavelength is [L]. It comes from wavelength = length.
What is the SI unit of wavelength?
The SI unit of wavelength is the metre (m).
Which quantities have the same dimensions as wavelength?
Wavelength shares [L] with length, displacement, radius of gyration, mean free path, amplitude, focal length, fringe width, de Broglie wavelength. Equal dimensions do not make them the same quantity.