Electrostatic Potential and Capacitance

This set of vocabulary flashcards covers core concepts of electrostatic potential, work, energy, conductors, dielectrics, and capacitance as discussed in the lecture notes.

Conservative Force

A force where the work done in moving a particle between two points is independent of the path taken (e.g., gravitational force, electrostatic force, elastic spring force).

Electrostatic Potential ($V$)

The amount of work done in bringing a unit positive test charge from infinity to a point in the region of an electric field, expressed as $V = \frac{W}{q_0}$.

Volt ($V$)

The SI unit of electrostatic potential; potential is $1\,V$ when the work done is $1\,J$ to bring a positive test charge of $1\,C$ from infinity to a point.

Dimensional formula of Potential ($V$)

$V = \frac{W}{q} = \frac{ML^2T^{-2}}{AT} = ML^2T^{-3}A^{-1}$.

Electrostatic Potential Difference ($\Delta V$)

The amount of work done in moving a unit positive charge from one point to another point ($\Delta V = V_B - V_A$).

Electric Potential due to a point charge

The potential at a point at a distance $r$ from a point charge $+Q$ is given by $V = \frac{Q}{4\pi\epsilon_0 r}$.

Equipotential Surface

Any surface that has the same electrostatic potential at every point.

Electrostatic Shielding

The phenomenon of making a region free from external electric fields based on the fact that the electric field vanishes inside the cavity of a hollow conductor.

Faraday's Cages

Hollow conductors used to protect instruments from external electric fields by enclosing them within.

Dielectric

A substance, essentially an insulator, which does not allow the flow of charges through it but permits them to exert electrostatic forces on one another.

Polar Molecules

Molecules in which the center of mass of positive charges and negative charges do not coincide, resulting in a permanent dipole moment (e.g., $H_2O$, $HCl$, $CO$, $CH_3OH$, $NH_3$).

Non-polar Molecules

Molecules in which the center of mass of positive and negative charges coincide, possessing no permanent dipole moment (e.g., $H_2$, $CO_2$, $N_2$, $CH_4$).

Polarisation Density ($P$)

The dipole moment per unit volume developed in a dielectric medium in the presence of an external electric field.

Electric Susceptibility ($\chi_e$)

A constant that describes the electrical behavior of the dielectric medium; for vacuum, $\chi_e = 0$.

Capacitor

A system of two conductors separated by an insulator, used for storing large amounts of electric charges.

Electrical Capacitance ($C$)

The ability of a conductor or capacitor to store electric charges, given by the ratio $C = \frac{Q}{V}$, where $Q$ is the charge and $V$ is the potential.

Farad ($F$)

The SI unit of capacitance; a capacitor has a capacity of $1\,F$ when a charge of $1\,C$ raises its potential by $1\,V$.

Dielectric Strength

The maximum electric field that a dielectric medium can withstand without breakdown.

Parallel Plate Capacitor

A device consisting of two large plane parallel conducting plates separated by a small distance $d$, with insulating material in between.

Dielectric Constant ($K$)

The ratio of the capacitance of a capacitor in a medium ($C_{med}$) to its capacitance in air ($C_{air}$).