Electrostatics Question 672
Question: It is required to hold equal charges $ q $ in equilibrium at the comers of a square. What charge when placed at the center of the square will do this?
Options:
A) $ -\frac{q}{2}(1+2\sqrt{2}) $
B) $ \frac{q}{2}(1+2\sqrt{2}) $
C) $ \frac{q}{4}(1+2\sqrt{2}) $
D) $ -\frac{q}{4}(1+2\sqrt{2}) $
Show Answer
Answer:
Correct Answer: D
Solution:
[d] $ AC=\sqrt{2l}=BD $ or $ BO=\frac{1}{\sqrt{2}} $
$ F _{BO}=F _{BD}+(F _{BA}+F _{BC})cos45{}^\circ $
Solving, we get $ Q=\frac{q}{4}(1+2\sqrt{2}) $ and Q should be negative of q.
