Numford

Induction, AC and EM wavesClass 12, Electromagnetic Induction

Dimensional formula of Self inductance

[M L2 T-2 A-2]

SymbolL SI unithenry (H)

Flux linked with a coil per unit current in the same coil. The henry is weber per ampere.

Derivation

How to get the dimensional formula of self inductance

  1. Start from the definition: self inductance = magnetic flux / electric current.
  2. velocity = length / time, so velocity is [L] / [T] = [L T-1].
  3. acceleration = velocity / time, so acceleration is [L T-1] / [T] = [L T-2].
  4. force = mass × acceleration, so force is [M] × [L T-2] = [M L T-2].
  5. electric charge = electric current × time, so electric charge is [A] × [T] = [T A].
  6. magnetic field = force / (electric charge × velocity), so magnetic field is [M L T-2] / ([T A] × [L T-1]) = [M T-2 A-1].
  7. area = length × length, so area is [L] × [L] = [L2].
  8. Put in the dimension of each part: [M L2 T-2 A-1] / [A].
  9. Add the powers of each base quantity: [M L2 T-2 A-2].
Same dimensions

Quantities with the dimensions [M L² T⁻² A⁻²]

Equal dimensions do not make them the same quantity. Compare self inductance with the others in the full grid.

Practice

Three questions on self inductance

1Which of these has the same dimensions as self inductance?

2What is the SI unit of self inductance?

3Do self inductance and impedance have the same dimensions?

Try it

An equation that uses self inductance

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 asU = (1/2) L I2
U[M L2 T-2]1/2 L I2[M L2 T-2]
Dimensionally consistentEvery term is [M L2 T-2]
U = energy
Questions

Self inductance: quick answers

What is the dimensional formula of self inductance?

The dimensional formula of self inductance is [M L² T⁻² A⁻²]. It comes from self inductance = magnetic flux / electric current.

What is the SI unit of self inductance?

The SI unit of self inductance is the henry (H).

Which quantities have the same dimensions as self inductance?

Self inductance shares [M L² T⁻² A⁻²] with mutual inductance. Equal dimensions do not make them the same quantity.

Open the dimensional formula tool