Glossary
Charge Redistribution
The process by which charges within or on the surface of a conductor rearrange themselves in response to internal or external electric fields until electrostatic equilibrium is reached.
Example:
When you rub a balloon on your hair, the charge redistribution on both the balloon and your hair causes them to become oppositely charged, leading to static cling.
Electric Field (inside conductor)
The force per unit charge experienced by a test charge. Inside a conductor in electrostatic equilibrium, the net electric field is always zero.
Example:
If you place a conductor in an external electric field, charges within it will redistribute until the electric field inside the conductor becomes zero, shielding the interior.
Electric Potential
A scalar quantity representing the amount of electric potential energy per unit charge at a given point in an electric field. Charges move to equalize this value.
Example:
When you connect two charged conductors, electrons will flow until their electric potential is the same, much like water flowing between two connected tanks until the water levels are equal.
Electron Flow
The movement of negatively charged electrons from an area of higher electric potential to an area of lower electric potential, or vice versa, to achieve equilibrium.
Example:
In a lightning strike, a massive electron flow occurs from a negatively charged cloud to the positively charged ground, rapidly equalizing the potential difference.
Electrostatic Equilibrium
The state of a conductor where all charges are at rest, resulting in a zero net electric field inside the conductor and a constant electric potential throughout its volume.
Example:
A metal sphere sitting isolated in space, with its charges settled, is in electrostatic equilibrium, meaning no further charge movement occurs.
Geometry (of conductors)
The physical shape and configuration of a conductor, which significantly influences how charge distributes on its surface, especially at sharp points or close surfaces.
Example:
A lightning rod's sharp point is effective because its specific geometry concentrates charge, facilitating a controlled discharge during a storm.
Ground
An idealized reference point with zero electric potential that can absorb or provide an unlimited amount of charge without changing its potential.
Example:
Connecting an appliance to ground provides a safe path for excess charge to dissipate, preventing electrical shocks by maintaining a zero potential reference.
Induced Charge
Charges that appear on the surface of a conductor due to the presence of an external electric field, without direct contact or charge transfer from the external source.
Example:
When a negatively charged balloon is brought near a neutral wall, positive induced charges appear on the wall's surface closest to the balloon, causing them to attract.
Polarization
The separation of positive and negative charges within a neutral object (conductor or dielectric) due to an external electric field, leading to an induced dipole moment.
Example:
When a charged comb attracts small pieces of paper, it's because the comb causes polarization within the paper, aligning the paper's charges and creating an attractive force.