1. Tardigrade
  2. Question
  3. Physics
  4. Four electric charges +q , +q , -q and -q are placed at the corners of a square of side 2L ( see figure ). The electric potential at point A , midway between the two charges +q and +q , is <img class=img-fluid question-image alt=Question src=https://cdn.tardigrade.in/q/nta/p-4pfhhd6o0jrs.png />

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. Four electric charges $+q$ , $+q$ , $-q$ and $-q$ are placed at the corners of a square of side $2L$ ( see figure ). The electric potential at point $A$ , midway between the two charges $+q \, $ and $+q$ , is

Question

NTA AbhyasNTA Abhyas 2020Electrostatic Potential and Capacitance

Solution:

Distance of point A from the two +q charges = L.
Distance of point A from the two -q charges = $\sqrt{\mathrm{L}^2+(2 \mathrm{~L})^2}$=$\sqrt {5L}$
Solution
$\therefore $ $\left(\text{V}\right)_{\text{A}} = \left(\frac{\text{Kq}}{\text{L}} \times 2\right) - \left(\frac{\text{Kq}}{\sqrt{5} \text{L}} \times 2\right)$
$= \frac{2 \text{Kq}}{\text{L}} \left[\right. 1 - \frac{1}{\sqrt{5}} \left]\right.$
$= \frac{1}{4 \pi \left(\in \right)_{0}} \cdot \frac{2 \text{q}}{\text{L}} \left(1 - \frac{1}{\sqrt{5}}\right)$