# Homework Help: Current, direction of flow and potential difference in a circuit

1. Feb 23, 2010

### coz

1. The problem statement, all variables and given/known data

The question is 'Calculate the current in each of the three resistors in the circuit in Figure 4 and indicate the direction of current flow. What is the potential difference between A and B?'

View attachment Qu 4.pdf

2. Relevant equations

Kirchhoff's first and second laws, Ohm's law

3. The attempt at a solution

I assigned arbitary directions to the circuit and using Kirchhoff's first and second laws I have worked out the current in each of the three resistors to be:

i1 = 0.4A
i2 = -0.2A
i3 = 0.2A

I then decided that the current i2 flows in the opposite direction to what I have marked, as it is negative.

To work out the potential difference between A and B can I just use Ohm's law

V = iR
V = 0.2A x 10 $$\Omega$$
V = 2, so the potential difference between A and B is 2?

Thanks

Last edited: Feb 23, 2010
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