# I There are two solutions in one image-charge problem?

1. Dec 22, 2016

### garylau

Sorry
there are two different solutions in one question
!! which one is correct??
the first one is written by griffiths

the second one is written by a lecturer.

they are not consistent in the same question
So which one is correct?
thank you

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Last edited: Dec 22, 2016
2. Dec 22, 2016

### BvU

Well, in the preceding section Griffiths gives an alternative way to calculate the work !
It's not too complicated to integrate the force you calculated over the path bx = ay from $\infty$ to $(a,b)$ .
(And you can simplify by setting $a=b$ -- all you're after is factor of 2).

This thread should be in the homework forum.

3. Dec 22, 2016

### Staff: Mentor

It looks more like a studying question so far, so we can leave it here for now.