Directions: (21-25) |
Electric Potential Energy |
This energy possessed by a system of charges by virtue of their positions. When two like charges lie infinite distance apart, their potential energy is zero because no work has to be done in moving one charge at infinite distance from the other. |
In carrying a charge q from point B, work done \[W=q\left( {{V}_{A}}-{{V}_{B}} \right)\] This work may appear as charge in KE/PE of the charge. The potential energy of two charges \[{{q}_{1}}\] and \[{{q}_{2}}\] at a distance r in air is \[\frac{{{q}_{1}}{{q}_{2}}}{4\pi {{\varepsilon }_{0}}r}\]. It is measured in joule. It may be positive, negative or zero depending on the signs of \[{{q}_{1}}\] and \[{{q}_{2}}\]. |
A) \[k{{e}^{2}}\]
B) \[{{e}^{2}}/2\]
C) \[-k{{e}^{2}}/2\]
D) zero
Correct Answer: C
Solution :
\[W={{\left( P.E. \right)}_{final}}-{{\left( P.E. \right)}_{initial}}\] \[=\frac{k{{e}^{2}}}{2}-\frac{k{{e}^{2}}}{1}=\frac{-k{{e}^{2}}}{2}\]You need to login to perform this action.
You will be redirected in
3 sec