Potential Difference between two points in battery

In summary, the terminal-to-terminal potential difference in a battery with an EMP of 12v and an internal resistance of 2 ohms is equal to 12v when there is no current flowing (c). When current flows from the negative to positive terminal (a), the potential difference is less than 12v. However, when current flows from the positive to negative terminal (b), the potential difference is greater than 12v due to a higher voltage source forcing current backwards through the battery.
  • #1
mb85
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more so help with the concept than anything else.

A battery has an EMP of 12v and an internal resistance of 2 ohms. Is the terminal-to-terminal potential difference greater than, less than, or equal to 12v if the current in the battery is from a) from the neg to pos. terminal b) from pos to neg terminal c) zero?

I realize that you loose potential in going from a neg. to pos. terminal.
so for:
a) +E -iR = 0
b) -E + iR = 0
c) they are equal.

im just a little foggy on why b is greater than 12V.
thanks in advance!
 
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  • #2
mb85 said:
more so help with the concept than anything else.

A battery has an EMP of 12v and an internal resistance of 2 ohms. Is the terminal-to-terminal potential difference greater than, less than, or equal to 12v if the current in the battery is from a) from the neg to pos. terminal b) from pos to neg terminal c) zero?

I realize that you loose potential in going from a neg. to pos. terminal.
so for:
a) +E -iR = 0
b) -E + iR = 0
c) they are equal.

im just a little foggy on why b is greater than 12V.
thanks in advance!
If E and i are positive, b) should be E + iR and neither a) nor b) should be set = 0. These are the terminal voltages. They are not zero.

In b), something out there (perhaps a higher voltage battery, or a battery charger) is forcing current "backwards" through the battery
 
Last edited:
  • #3
oh i was doing the loop rule by accident. that's why i was setting them equal to zero.
 

FAQ: Potential Difference between two points in battery

What is potential difference between two points in a battery?

Potential difference, also known as voltage, is the difference in electric potential energy between two points in a battery. It is the driving force that allows electric current to flow from one point to another.

How is potential difference measured in a battery?

Potential difference is measured in volts (V) using a voltmeter. The voltmeter is connected between the two points in the battery and the reading indicates the potential difference between them.

Why does potential difference exist in a battery?

Potential difference exists in a battery because of the separation of charges between its two terminals. The positive terminal has an excess of positive charge while the negative terminal has an excess of negative charge. This difference in charge creates a potential difference between the two terminals.

What is the relationship between potential difference and current in a battery?

The potential difference in a battery is directly proportional to the electric current flowing through it. This means that as the potential difference increases, the current also increases, and vice versa.

How does the potential difference change as a battery discharges?

As a battery discharges, the potential difference between its two terminals decreases. This is because the separation of charges decreases as the battery runs out of stored energy, resulting in a decrease in potential difference and electric current flow.

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