A 2.00 nC charge is placed on the x-axis at x = −3.00 cm, another 2.00 nC charge is placed on the x-axis at x = 3.00 cm, and a third 2.00 nC charge is placed on the y-axis at y = 3.00 cm. What is the potential at the origin?

Question

Quizplus · Accepted Answer

The potential at a point due to a point charge is given by $V = \frac{kq}{r}$, where $V$ is the potential, $k$ is Coulomb's constant ($9 \times 10^9 \, \text{Nm}^2/\text{C}^2$), $q$ is the charge, and $r$ is the distance from the charge to the point. Since potential is a scalar quantity, it adds algebraically. The distance of each charge from the origin is 0.03 m (3.00 cm). The total potential at the origin due to all three charges is the sum of the potentials due to each charge:$$V_{\text{total}} = 3 \times \frac{kq}{r} = 3 \times \frac{(9 \times 10^9) \times (2 \times 10^{-9})}{0.03} = 3 \times 600 = 1800 \, \text{V}.$$

A 200 NC Charge Is Placed on the X-Axis at X