How Do You Calculate the EMF of a Cell in a Circuit?

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The discussion revolves around calculating the electromotive force (EMF) of a cell in a circuit, specifically addressing the equation EMF = I(R + r). Participants express confusion about the application of this equation and the use of Kirchhoff's laws. The correct EMF is determined to be 1 volt, but there is uncertainty regarding the treatment of voltage readings and the necessity to consider one as negative. Kirchhoff's voltage law is mentioned as essential for understanding the circuit, yet some participants admit to not fully grasping it. Ultimately, the conversation highlights the importance of applying Kirchhoff's principles to resolve circuit calculations accurately.
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I know I need to find the difference of of the volts about the 2 resistors.

it ends up being 1 volt, but how the hell does i(R+r)=emf come into that
 
DeanBH said:
I know I need to find the difference of of the volts about the 2 resistors.

it ends up being 1 volt, but how the hell does i(R+r)=emf come into that
That equation is valid only for two resistors in series, i.e. where a cell has an internal resistance r and is connected to a load resistance R.

As I said previously, you need to apply Kirchoff's laws here.
 
I did, the answer is 1

just doesn't make sense.
 
DeanBH said:
I did, the answer is 1

just doesn't make sense.
I also have emf = 1V. So what doesn't make sense?
 
Why do i have to count one of those volt readings as negative, and why inst it 1/r it looks like a a parallel
 
DeanBH said:
Why do i have to count one of those volt readings as negative, and why inst it 1/r it looks like a a parallel
What is Kirchoff's voltage/loop law?
 
Hootenanny said:
What is Kirchoff's voltage/loop law?

no idea
 
  • #10
Hootenanny said:
As I said previously, you need to apply Kirchoff's laws here.
DeanBH said:
I did, the answer is 1
Hootenanny said:
What is Kirchoff's voltage/loop law?
DeanBH said:
no idea
How can you apply Kirchoff's voltage law if you don't know what it is?
 
  • #11
guessed, that the volts in the battery would have to make up for the difference. but why is the amps 0.06 out of 0.032, if the volts were 5.2 instead of 4.2 in the right part of the circuit it wouldn't fit the rule RI=v
 
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