Question

Imagine that two charged objects are the system of interest. When the objects are infinitely far from each other, the electric potential energy of the system is zero. When the objects are close to each other, the electric potential energy is positive. Which of the following statements is(are) incorrect

(a) Both objects are positively charged.
(b) Both objects are negatively charged.
(c) One object is negatively charged and the other one is positively charged.

Answer 1

Answer: Option (c) is the correct answer.

Explanation:

It is known that the expression for potential energy related to charges and distance between their separation is as follows.

           $U_{q} = \frac{kq_{1}q_{2}}{r}$  

where,   $q_{1}$ and $q_{2}$ are two charges

                r = distance of separation between the charges

               k = electrostatic constant

So, when both the charges are carry the same charge and r is small then the value of potential energy will be positive in nature.

Whereas if the distance of separation between the charges is infinitely large then the potential energy calculated will be zero everywhere.

Thus, we can conclude that the statement one object is negatively charged and the other one is positively charged, is incorrect.