# Confusion Regarding Potential Reference Point

#### jegues

Joined Sep 13, 2010
733
See figure attached for problem statement, solution provided and my solution.

I'm getting confused about the reference point for the potential.

First find the potential at point z with reference at infinity,

$$\phi(z) - \phi(\infty) = \alpha$$

Now find the potential at point z=0 with reference at infinity,

$$\phi(0) - \phi(\infty) = \beta$$

Now the potential at z with the reference at z=0, which is the same as the voltage difference between the individual voltages at z and z=0 with their reference point at infinity. (Is this statement true?)

$$\alpha - \beta = \phi(z) - \phi(0)$$

The question wants me to solve for,

$$\phi(z)$$

but it seems as though I've given them,

$$\phi(z) - \phi(0)$$

What am I interpreting differently? What am I confusing myself with?

Thanks again!

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#### Zazoo

Joined Jul 27, 2011
114
Phi(z=0) = 0 (this is the reference). So the two expresions are the same.