Physics

Physics

Problem

Which expression gives the change in electric potential energy ΔU\Delta U of a point charge qq that is moved between two locations with electric potentials V1V_1 and V2V_2? a) ΔU=12 q (V2−V1)\Delta U=\dfrac12\,q\,(V_2-V_1) b) ΔU=q (V1−V2)\Delta U=q\,(V_1-V_2) c) ΔU=q (V2−V1)\Delta U=q\,(V_2-V_1) d) ΔU=q ∣ V2−V1 ∣\Delta U=q\,|\,V_2-V_1\,|
Intuitive explanation

Electric potential energy change is fundamentally about how much work the electric field does (or against which you must work) to move a charge. The key insight is that electric potential is defined as potential energy per unit charge, so the change in potential energy is simply the charge multiplied by the difference in potential at those two locations. Think of potential as the "height" in an electric landscape—moving a charge between two heights tells you exactly how much energy changes.

Intuitive explanation

Electric potential energy change is fundamentally about how much work the electric field does (or against which you must work) to move a charge. The key insight is that electric potential is defined as potential energy per unit charge, so the change in potential energy is simply the charge multiplied by the difference in potential at those two locations. Think of potential as the "height" in an electric landscape—moving a charge between two heights tells you exactly how much energy changes.

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