Working out EMF of a cell

  • Thread starter DeanBH
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In summary: Ri and it would be 5.2 amps not 0.06How can you apply Kirchoff's voltage law if you don't know what it is?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/Ri and it would be 5.2 amps not 0.06
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  • #3
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
 
  • #4
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.
 
  • #5
I did, the answer is 1

just doesn't make sense.
 
  • #6
DeanBH said:
I did, the answer is 1

just doesn't make sense.
I also have emf = 1V. So what doesn't make sense?
 
  • #7
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
 
  • #8
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?
 
  • #9
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
 
Last edited:

What is EMF of a cell?

EMF (electromotive force) of a cell is the potential difference between the positive and negative terminals of a cell. It is a measure of the cell's ability to generate an electrical current.

How is EMF of a cell measured?

EMF of a cell is measured in volts (V) using a voltmeter. The voltmeter is connected to the positive and negative terminals of the cell to measure the potential difference.

Why is it important to know the EMF of a cell?

Knowing the EMF of a cell is important in understanding its electrical properties and how it can be used in various applications. It also helps in determining the efficiency and performance of a cell.

What factors affect the EMF of a cell?

The EMF of a cell can be affected by the type of materials used in the cell, the concentrations of the electrolytes, and the temperature. Other factors such as internal resistance and external load can also affect the EMF.

How can the EMF of a cell be increased?

The EMF of a cell can be increased by using materials with higher electrode potentials, increasing the concentration of the electrolytes, and decreasing the temperature. However, it is important to note that increasing the EMF may also lead to a decrease in the cell's lifetime.

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