A) \[-\frac{4{{q}^{2}}}{\sqrt{2}\pi {{\varepsilon }_{0}}l}\]
B) \[\frac{\sqrt{3}{{q}^{2}}}{4\pi {{\varepsilon }_{0}}l}\]
C) \[\frac{4{{q}^{2}}}{\sqrt{2}\pi {{\varepsilon }_{0}}l}\]
D) \[-\frac{4{{q}^{2}}}{\sqrt{3}\pi {{\varepsilon }_{0}}l}\]
Correct Answer: D
Solution :
[d] Length of body diagonal \[=\sqrt{3}\ell \] \[\therefore \]Distance of center of cube from each comer \[r=\frac{\sqrt{3}}{2}\ell \] \[\text{P}\text{.E}\text{. at center= 8 }\!\!\times\!\!\text{ Potential Energy due to}\] \[A=8\times \frac{Kq\times \left( -q \right)}{r}\] \[=8\times \frac{1}{4\pi {{\varepsilon }_{0}}\sqrt{3}\ell }\times 2\times q\times \left( -\,q \right)=\frac{-4{{q}^{2}}}{\sqrt{3}\pi {{\varepsilon }_{0}}\ell }\]You need to login to perform this action.
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