Numford
Equation check

Check the dimensional correctness of c = 1/√(μ₀ε₀)

Speed of light from μ₀ and ε₀. Maxwell's result that links light to electricity and magnetism.

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 asc = 1 / sqrt(μ0 ε0)
c[L T-1]1/sqrt(mu0 epsilon0)[L T-1]
Dimensionally consistentEvery term is [L T-1]
μ0 = permeability of free spaceε0 = permittivity of free space
Working

Step by step

1. What each symbol stands for

2. The dimensions of each term

  • c [L T-1] [L T-1]
  • 1/sqrt(mu0 epsilon0) 1 / sqrt([M L T-2 A-2] × [M-1 L-3 T4 A2]) [L T-1]

3. Compare

Every term has dimensions [L T-1], so the equation is dimensionally consistent.

What a dimension check shows

What it proves and what it does not

It can show

  • Every term that is added or subtracted has the same dimensions, so the sum makes sense.
  • Both sides of the equals sign have the same dimensions.
  • Angles inside sin, cos and similar functions are pure numbers.

It cannot show

  • A pure number such as 1/2 or 2π has no dimensions, so a check cannot see a missing or wrong one.
  • Two quantities with the same dimensions, such as work and torque, cannot be told apart.
  • A sign error or a wrong power that keeps the dimensions equal goes unnoticed.

Matching dimensions are necessary but not sufficient. Pure numbers such as 1/2 or 2π have no dimensions, so a check cannot see them, and an equation with matching dimensions can still be wrong.

Quantities used

Look up each quantity

Questions

c = 1/√(μ₀ε₀): quick answers

Is c = 1/√(μ₀ε₀) dimensionally correct?

Yes. Every term has the same dimensions, [L T⁻¹], so c = 1/√(μ₀ε₀) is dimensionally consistent. That does not prove the equation itself is correct.

Does a dimension check prove c = 1/√(μ₀ε₀) is right?

No. A check can show that an equation is wrong, but it cannot show that it is right. Pure numbers such as 1/2 and 2π have no dimensions, so the check cannot see them.

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