How does emf relate to current, elec potential, & resistance

In summary, the conversation discusses the relationship between emf, current, electrical potential, and resistance in the context of various equations. The equations include V = IR, V = emf - IR, and R = V/I. The main question is how emf relates to current, electrical potential, and resistance, and specifically how V = emf - IR if V = IR. The conversation also touches on the usefulness of ΔV (change in electric potential) and V (electric potential) in calculations, and asks for clarification on when each is appropriate to use. More context, such as the specific circuit being discussed, would be needed for a more complete understanding.
  • #1
PhysicsBoyMan
33
0

Homework Statement



How does emf relate to current, electrical potential, and resistance? Specifically, in the context of the equations I have posted below.

Homework Equations



V = IR [/B]where V is electric potential, I is current, and R is resistance.

V = emf - IR

How can V = emf - IR if V = IR ?
Here is another similar example:

R = V/I

R = (emf - V) / I


The Attempt at a Solution


[/B]
emf seems to be some kind of change to the original electric potential of a circuit. emf - IR seems to calculate ΔV. Am I right about this? As far as I can tell, Ohm's law uses V, not ΔV. When is ΔV useful and when is V useful? Or do I have this all wrong?Thanks.
 
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  • #2
I think some context is missing.

Can you draw the circuit for the examples you mention. Are you talking about a battery with internal resistance or a DC motor or ?
 

Related to How does emf relate to current, elec potential, & resistance

1. How does EMF relate to current?

Electromotive force (EMF) is the amount of energy per unit charge that is supplied by a source, such as a battery, to move a charge through a circuit. The current in a circuit is directly proportional to the EMF, meaning that as the EMF increases, the current also increases. This relationship is described by Ohm's Law, which states that current (I) is equal to EMF (E) divided by resistance (R): I = E/R.

2. How does EMF relate to electric potential?

Electric potential, also known as voltage, is the measure of the potential energy per unit charge at a specific point in an electric field. EMF is the force that causes current to flow, and it is directly related to the electric potential difference between two points. In other words, the higher the EMF, the greater the electric potential difference between two points.

3. How does EMF relate to resistance?

Resistance is the measure of how much a material or device opposes the flow of electric current. In a circuit, resistance limits the current that can flow, and it is inversely proportional to the EMF. This means that as the EMF increases, the resistance decreases, and more current can flow through the circuit.

4. How does EMF affect the flow of current in a circuit?

EMF is responsible for creating the potential difference that allows current to flow through a circuit. The higher the EMF, the more force is applied to move charges through the circuit, resulting in a larger current. However, the resistance in the circuit also affects the flow of current, as described by Ohm's Law.

5. How does EMF impact the performance of electronic devices?

EMF plays a crucial role in the operation of electronic devices. Without it, devices such as batteries and generators would not be able to supply the necessary energy for current to flow. However, high levels of EMF can also cause interference and disrupt the functioning of electronic devices. This is why electromagnetic shielding and proper grounding are important in the design and use of electronic devices.

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