Physics · Ch 1 — Electrostatics
ELECTROSTATIC POTENTIAL AND POTENTIAL ENERGY
ELECTROSTATIC POTENTIAL AND POTENTIAL ENERGY
In mechanics, potential energy is defined only for conservative forces, such as gravity, whose gravitational potential energy was introduced in Class 11 (Unit 6). Coulomb's electrostatic force, like gravity, is an inverse-square-law force and is likewise conservative -- the work done in moving a charge between two points does not depend on the path taken, only on the two endpoints. This conservative property makes it possible to define an electrostatic potential energy for any configuration of charges, exactly as gravitational potential energy is defined for configurations of masses, and a related per-unit-charge quantity called the electric potential, which tur …
What this figure shows. A dipole is shown being rotated slowly, by an external agent, from one orientation to another against the restoring/aligning torque of a surrounding field, with the work the external agent must supply during the rotation highlighted as the quantity that ends up stored in the system. This is the general mechanics idea -- that the work done against a conservative force in changing a system's configuration equals the increase in that system's potential energy -- illustrated here with a dipole as a concrete lead-in, before the formal expressions for electrostatic potential and potential energy are derived in the nu …