# Electrical potential and current question

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

A point source current has an unknown current with a conductivity S. Q, representing the electrical potential, is .1 V at 5 cm away from the point source and is .005 V when 10 cm away. Find the current and the conductivity.

**2. Relevant equations**

I think these 2 are most relevant, say S is conductivity:

1) (1/S4pi)∫(I*dv)/r

2) (1/S4pi)(I/r)

**3. The attempt at a solution**

OK, so what I tried to do was a system of equations since we have 2 unknowns using equation 2, but what keeps happening is that my variables cross out every time so its like Im solving for nothing. This makes me think I need to use equation 1, but Im not sure how I should apply it. I think I should subtract the potentials to get dv, but dont know where to go from there.

Also, sorry if this is in the wrong section. Wasnt sure where exactly I should put it.

http://ift.tt/NWVmBF

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