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

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SUMMARY

The discussion centers on the relationship between electromotive force (emf), current, electrical potential, and resistance, specifically using the equations V = IR and V = emf - IR. The participant questions how V can equal both emf - IR and IR simultaneously, suggesting that emf represents a change in the original electric potential of a circuit. The distinction between using ΔV and V is also explored, indicating that ΔV is relevant in certain contexts, such as circuits with internal resistance.

PREREQUISITES
  • Understanding of Ohm's Law (V = IR)
  • Familiarity with the concept of electromotive force (emf)
  • Knowledge of electrical potential and resistance in circuits
  • Basic circuit analysis skills
NEXT STEPS
  • Study the concept of internal resistance in batteries and its effect on circuit performance
  • Learn about the application of Kirchhoff's Voltage Law in circuit analysis
  • Explore the differences between ΔV and V in practical circuit scenarios
  • Investigate the role of emf in AC vs. DC circuits
USEFUL FOR

Students studying electrical engineering, physics enthusiasts, and anyone seeking to deepen their understanding of circuit dynamics and the principles governing current and resistance.

PhysicsBoyMan
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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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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 ?
 

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