# Find the potential Difference

#### looi76

1. Homework Statement
http://img241.imageshack.us/img241/1087/09052008hf9.png [Broken]
What is the potential difference across (i) AB (ii) BC.
2. Homework Equations
??
3. The Attempt at a Solution
(i) $$\frac{200}{400} \times 6 = 3V$$

Is this right?

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#### BishopUser

I think the easiest way to do this would be to use equivalent resistances to find the current. After that it is very easy

#### looi76

I didn't understand...

#### alphysicist

Homework Helper
Hi looi76,

We know the total resistance between A and B is 200 ohms. What is the total resistance between B and C?

#### looi76

The total resistance between B and C is 100 because they are connected in parallel. So, $$\frac{200}{(100 + 200)} \times 3 = 2V$$

Is this correct?

#### Defennder

Homework Helper
No, that is not the total resistance between B and C. They are both in parallel. What is the formula for resistance connected in parallel?

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