# Calculating potential difference

1. Oct 26, 2008

### sallyishyper

I have done 1, i cant get the right answer for question 2. i seem to be getting minus7.5 volts. i know thats not anywhere near right because you can't get a minus voltage. i have tried many different ways to do this and i still cant get the right answer

To get question 1 i used ohms law which gave me the two answers shown in the attachment, for question 2 i tried using the same method, but that gave me the wrong answer so i tried finding the conductance and from the resistance and the current, but that gave me - 7.5 volts. i ma very confused an i think i might be missing something very simple

View attachment 16093

Last edited: Oct 27, 2008
2. Oct 28, 2008

### alphysicist

Hi sallyishyper,

Your attachment does not seem to be there.

3. May 3, 2010

### tmusgrove

I couldn't get the attachment either, says that there is an error.

4. May 3, 2010

### tiny-tim

Hi sallyishyper!

Can you give us the url of your picture?