Calculating EMF and Current in a Circuit with Internal Resistance

AI Thread Summary
To calculate the current in a circuit with a 5.60-ohm resistor and a battery with 0.200-ohm internal resistance and a terminal voltage of 10.0V, the formula EMF = terminal voltage + (I)(Rint) is used. The current (I) can be derived from the equation 10 = 5.6I, resulting in I = 1.79A. The EMF of the battery is then calculated as EMF = 10 + (1.79)(0.2), yielding an EMF of approximately 10.36V. Clarification on the resistor's value is necessary, as there is a discrepancy between 5.6 and 5.8 ohms mentioned in the discussion. Understanding these calculations is crucial for exam preparation.
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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