what are electromotive force (emf) and potential difference? and what is the difference between the two?
please dont make your answer sound like a physics text book!
thank you
2007-01-23 13:24:53 · 5 answers · asked by girlwiththegoodies 3 in Science & Mathematics ➔ Physics
EMF is positive and propels current from one point to another, while PD is more the difference in voltage between 2 points or more in an electric circuit
2007-01-23 13:31:56 · answer #1 · answered by Zhughu 2 · 0⤊ 0⤋
Think of a battery, sitting by itself.....not connected to anything. The energy that is stored in that battery is emf. It cannot be measured directly...explained next.
When the battery is connected in an electric circuit, a current flows through it. But some of the energy that was originally in the battery is used up in moving across the battery terminals. The resultant energy(energy left) is the potential difference. Only this can be measured directly(using a voltmeter). Emf cannot be measured directly because, as soon as you connect the battery to something, it is no longer the emf that you are measuring.
Just remember,
emf =~ when not connected
Potential diff =~ connected in a circuit.
2007-01-23 14:09:39 · answer #2 · answered by me 4 · 0⤊ 0⤋
When some kind of closed circuit is connected between some type of voltage source, like a battery, current will flow from the source, through the circuit, and back into the battery. ELECTROMOTIVE FORCE is the energy that propels the current.
If you remove the closed circuit from between the battery terminals current will not flow but the POTENTIAL DIFFERENCE is still present between the batterie's terminals.
2007-01-23 13:33:58 · answer #3 · answered by Chug-a-Lug 7 · 0⤊ 0⤋
I've read the first three answers you've received... and believe that they are factually correct. I'll add a suggestion that you consider EMF as the voltage applied to the circuit. Now, all that voltage is going to be "used up" through the circuit. The potential difference is the amount of that voltage - the electrical "pressure" which is needed to force its way through each individual resistance... found by the formula E = IR.
2016-05-24 02:41:20 · answer #4 · answered by Kelley 4 · 0⤊ 0⤋
A ball placed on an inclined plane comes down from TOP TO BOTTOM because of height H.
In between the plane, it moves from A to B, because of the height difference AB = h.
In analogy, the maximum potential difference or E.M.F. corresponds to the maximum height H
The potential difference between two points in an electrical circuit corresponds to the small height h
For detailed answer refer text book.
2007-01-23 14:04:21 · answer #5 · answered by Pearlsawme 7 · 0⤊ 0⤋