Numford

Induction, AC and EM wavesClass 12, Electromagnetic Induction

Dimensional formula of Mutual inductance

[M L2 T-2 A-2]

SymbolM SI unithenry (H)

Flux linked with one coil per unit current in a neighbouring coil. It has the same dimension as self inductance.

Derivation

How to get the dimensional formula of mutual inductance

  1. Start from the definition: mutual 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 mutual inductance with the others in the full grid.

Practice

Three questions on mutual inductance

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

2What is the SI unit of mutual inductance?

3Do mutual inductance and Poynting vector have the same dimensions?

Questions

Mutual inductance: quick answers

What is the dimensional formula of mutual inductance?

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

What is the SI unit of mutual inductance?

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

Which quantities have the same dimensions as mutual inductance?

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

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