# Dimensions of Electric Charge

1. Mar 4, 2012

### azabak

If you search electric charge on the German Wikipedia (search electric charge on Wikipedia and click on the "Deutsch" blue link on the left side) its dimension is defined as "M^(1/2)*L^(3/2)*T^(-1)". I always thought of electric charge as fundamental property that by definition has its own dimension "Q". Could someone please explain me this?
azabak

Last edited: Mar 4, 2012
2. Mar 4, 2012

### Staff: Mentor

This comes about by defining the unit of charge using Coulomb's Law: two charges, each with one unit of charge, separated by one unit of distance, exert one unit of force on each other. Combine this with the definition of the unit of force in terms of units of mass, length and time.

3. Mar 4, 2012

### azabak

Is this the definition of electric charge? If so it makes the Coulomb's Constant dimensionless.

4. Mar 5, 2012

### Staff: Mentor

It's a definition of electric charge.

Yes, in such a system of units. See for example

http://en.wikipedia.org/wiki/Gaussian_units

5. Mar 5, 2012

### azabak

I think this definition is, somehow, misleading assuming electric charge as a mechanical unit since all other electromagnetic quantities depend on the definition of electric charge.