# about emf and voltage

#### recca02

Joined Apr 2, 2007
1,214
Electromotive force (or potential) of a body is the work done in joules to bring a unit electric charge from infinity to the body.
can the same be said for velocity?
come to think of it maybe we can call mass a stable form of energy??

edit:uzair can also refer this.
http://en.wikipedia.org/wiki/Electromotive_force.

#### Dave

Joined Nov 17, 2003
6,970
I am now able to conclude the discussion as:The emf is same as voltage but it is used in difeferent sense.Thy have same units and we must not confuse both terms.We should have a mind-set like a voltmeter (because it views both as same and equally measures them).Am I right?
Yes. My advice would be to ignore EMF and talk about voltage and potential difference in the general sense, and a voltage source when talking about a source device such as a battery etc.

By that logic... would mass be energy? - measured in Joules per square V?

E = 1/2 MV^2 ergo M = 1/2 E / V^2
Indeed so, something Einstein came to realise. Incidentally Einstein's work on the equivalence can be directly derived from Maxwell's Equation which were published some 40-years earlier. Maxwell's Equations truly are a magnificent piece of science and intuition.

Dave

#### techroomt

Joined May 19, 2004
198
you've been provided much good information, and it seems to be a matter of symantics. the "quantity" (e.g. length, weight, speed, etc. ) is emf. electro-motive force is that force needed to move electrons. the "unit of measure" for the quantity is the volt. the voltage (synonym potential)then would be the amount of volts.

#### BlueDevry

Joined Dec 26, 2007
22
So I guess power source would also be a good term to use when describing the voltage source ?

#### recca02

Joined Apr 2, 2007
1,214
Voltage sources are called so because they provide rated voltages at any load.
the same is not true for power hence rating a source in terms of power is going to be difficult.
of course m/c like generators are rated for max power in terms of VA but that is due to metallurgical limitations.