Electrostatic Potential Energy – Rankers Physics
Topic: Electrostatics
Subtopic: Electric Potential Energy

Electrostatic Potential Energy

Assertion (A): When two positive point charges move away from each other, their electrostatic potential energy decreases.
Reason (R): Change in potential energy between two points is equal to the work done by electrostatic forces.
 
(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(3) (A) is true but (R) is false
(4) Both (A) and (R) are false

Solution:

Assertion (A): Electrostatic potential energy between two positive charges is \(U = k \frac{q_1 q_2}{r}\). If they move away, \(r\) increases, thus \(U\) decreases. So (A) is true.


Reason (R): The change in potential energy is defined as the negative of the work done by conservative forces (like electrostatic force): \(Delta U = -W_{electrostatic}\). So (R) is false.nTherefore, (A) is true and (R) is false.

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