# potential difference

Discussion in 'Homework Help' started by GMChandio, Feb 26, 2015.

1. ### GMChandio Thread Starter New Member

Feb 26, 2015
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0
a battery of 6 volts is short circuited by a copper wire. What will be the potential difference across its terminals?
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According to me it should be 0, as the battery has short circuited so their should be no charge flow so it should be zero. But the answer is 4, HOW?

2. ### Veracohr Well-Known Member

Jan 3, 2011
540
75
You're correct the answer is 0, but you're not correct in the reason why.

An answer of 4 is wrong.

3. ### MikeML AAC Fanatic!

Oct 2, 2009
5,450
1,066
Was the internal resistance of the battery mentioned in the problem statement. Perhaps the 4 refers to 4A, which might be the short-circuit current.

4. ### crutschow Expert

Mar 14, 2008
12,527
3,066
If can be 4V only if the resistance of the wire is twice that of the battery internal impedance.

5. ### WBahn Moderator

Mar 31, 2012
17,446
4,699
So if you short out your car battery, do you REALLY expect there to be no charge flow?

Always, always, ALWAYS ask if the answer makes sense!

The answer most certainly is NOT equal to 4, if for no other reason than 4 is a number and not a voltage.

Always, always, ALWAYS track your units!

6. ### MrChips Moderator

Oct 2, 2009
12,227
3,280
In theory, a 6V battery cannot be 6V and 0V at the same time.

In practice, you have to include real values.

A short is never 0Ω
The internal resistance of a real battery is never 0Ω.
A real battery cannot supply infinite current.