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EMF and internal resistance!

  • Thread starter Gunner1412
  • Start date
  • #1

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 :)
 

Answers and Replies

  • #2
Doc Al
Mentor
44,882
1,129

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?)
 
  • #3
5.6+0.2 for R1+ri... no?
 
  • #4
rl.bhat
Homework Helper
4,433
5
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:
  • #5
Doc Al
Mentor
44,882
1,129
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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