Question

A teacher takes two small foam objects which are charged as shown below. which of the following is a true statement about the electrical potential energy between the objects?

a. if she moves the objects closer together, the electrical potential energy between them will remain the same.
b. if she removes the charge from object 1, the electrical potential energy between the objects will increase.
c. if she moves the objects closer together, the electrical potential energy between them will decrease.
d. if she removes the charge from object 2, the electrical potential energy between the objects will remain the same.

Answer 1

When two oppositely charged objects are moved closer together, the electrical potential energy between them decreases; removing charge from either object also decreases the potential energy.

Step-by-step explanation:

The question is concerned with the effect on electrical potential energy when two charged objects interact. When two charges with the same sign are brought closer together, you have to do positive work which increases the system's potential energy. Therefore, the correct answer to the question is option (c): if she moves the objects closer together, the electrical potential energy between them will decrease, assuming one charge is positive and one is negative. If the charge is removed from either object, the electrical potential energy will decrease because the system will have less charge to contribute to potential energy interactions.