Calculating EMF and Current in a Circuit with Internal Resistance

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Homework Help Overview

The discussion revolves around calculating the electromotive force (EMF) and current in a circuit that includes a resistor and a battery with internal resistance. The problem involves understanding the relationships between terminal voltage, internal resistance, and current in the context of circuit analysis.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants discuss the equations related to EMF and terminal voltage, with some attempting to clarify the values of resistance used in calculations. There are questions about the correct resistance values and the interpretation of terminal voltage in relation to the circuit components.

Discussion Status

Several participants are actively engaging with the problem, offering insights and questioning the assumptions made about resistance values. There is a mix of agreement on certain calculations, but also some uncertainty regarding the values used, indicating a productive exploration of the topic.

Contextual Notes

Participants are working under the pressure of an impending exam, which may influence the urgency and focus of their inquiries. There is also a noted confusion regarding the specific values of resistance in the circuit, which remains unresolved.

Gunner1412
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Homework Statement



A 5.60ohm resistor is connected to a battery that has 0.200ohm internal resistance, and a terminal voltage of the battery is 10.0V. What is the current in the resistor? What is the emf of the battery?

Homework Equations



EMF=terminal voltage+(I)(Rint.)
V=RI

The Attempt at a Solution


E-I1Ri-I1R1=0
10=5.8I
I=1.72.
EMF=10+0.344=10.34

Help guys? Exam tomorrow at nine and this is the last problem I don't understand! Very much appreciated :)
 
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Gunner1412 said:

The Attempt at a Solution


E-I1Ri-I1R1=0
10=5.8I
I=1.72.
EMF=10+0.344=10.34
Looks good. (But is the resistor 5.6 or 5.8 ohms?)
 
5.6+0.2 for R1+ri... no?
 
E-I1Ri-I1R1=0
10=5.8I
I=1.72.
EMF=10+0.344=10.34

The terminal voltage is the voltage across the resistance. So V = IR1.= ER1/(R1 + Ri ).
 
Last edited:
Gunner1412 said:
5.6+0.2 for R1+ri... no?
No, 10V is the terminal voltage, which equals EMF - Iri. Thus 10 = I*5.6. (From your equation: E-I1Ri-I1R1=0.)
 

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