A square is $1.0 \mathrm {~m}$ on a side. Point charges of $+ 4.0 \mu \mathrm { C }$ are placed in two diagonally opposite corners. In the other two corners are placed charges of $+ 3.0 \mu \mathrm { C }$ and $- 3.0 \mu \mathrm { C }$. What is the potential (relative to infinity) at the midpoint of the square? $\left( k = 1 / 4 \pi \varepsilon _ { 0 } = 9.0 \times 10 ^ { 9 } \mathrm {~N} \cdot \mathrm { m } ^ { 2 } / \mathrm { C } ^ { 2 } \right)$

Question

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The potential at the midpoint of the square is due to the four charges. The potential due to the $+ 4.0 \mu \mathrm { C }$ charges is positive and the potential due to the $+ 3.0 \mu \mathrm { C }$ and $- 3.0 \mu \mathrm { C }$ charges is negative. The net potential is:$$V = \frac{1}{4\pi \varepsilon_0} \left(\frac{4 \times 4.0 \mu \mathrm { C}}{0.5^2 \mathrm { m}^2} + \frac{3.0 \mu \mathrm { C}}{0.5^2 \mathrm { m}^2} - \frac{3.0 \mu \mathrm { C}}{0.5^2 \mathrm { m}^2}\right) = 1.0 \times 10^5 \mathrm { V}$$

A Square Is 1.0 m1.0 \mathrm {~m}1.0 m On a Side Point Charges Of \mathrm

A Square Is $1.0 \mathrm {~m}$ On a Side Point Charges Of \mathrm