Electrostatics Practice Flashcards

Comprehensive vocabulary flashcards covering electric fields, electric potential, Gauss's law, electrostatic potential energy, dipoles, and conductors based on the lecture notes.

Quantization of Charge

The principle stating that electric charge present on a body is an integral multiple of elementary charge, expressed as $Q = n e$, where $e = 1.6 \times 10^{-19}\text{C}$ and $n$ is an integer.

Coulomb's Law

A fundamental law stating that the electrostatic force between two point charges in vacuum is $F = \frac{k q_1 q_2}{r^2}$, where the electrostatic constant $k = 9 \times 10^9\text{N}\text{m}^2/\text{C}^2$.

Permittivity of Free Space ($\varepsilon_0$)

A physical constant representing the capability of vacuum to permit electric fields, equal to $8.85 \times 10^{-12}\text{C}^2/\text{N}\text{m}^2$.

Electric Field Intensity (EFI)

The force experienced per unit positive test charge placed at a point in an electric field, given by $E = \frac{F}{q_0}$ with unit $\text{N/C}$.

EFI of Uniformly Charged Infinite Wire

The electric field intensity perpendicular to an infinitely long wire carrying linear charge density $\lambda$ at distance $r$, given by $E_\perp = \frac{2 k \lambda}{r}$.

EFI of Uniformly Charged Semi-Infinite Wire

The components of the electric field intensity at distance $r$ from the end of a semi-infinite wire, given by $E_\perp = \frac{k \lambda}{r}$ and $E_\parallel = \frac{k \lambda}{r}$.

Electric Flux ($\Phi$)

A scalar quantity measuring the electric field passing through a given surface area, defined as $\Phi = \int \mathbf{E} \cdot d\mathbf{A} = E A \cos(\theta)$ with unit $\text{N}\text{m}^2/\text{C}$.

Gauss's Law

A law stating that the total electric flux through any closed surface is equal to the net enclosed charge divided by $\varepsilon_0$, expressed as $\Phi = \oint \mathbf{E} \cdot d\mathbf{A} = \frac{q_{\text{enclosed}}}{\varepsilon_0}$.

EFI of Uniformly Charged Ring on Axis

The electric field on the axis of a uniformly charged ring of radius $R$ at distance $x$ from the center, expressed as $E = \frac{k Q x}{(R^2 + x^2)^{3/2}}$, which reaches its maximum magnitude at $x = \frac{R}{\sqrt{2}}$.

EFI of Conducting or Hollow Sphere

The electric field produced by a hollow or conducting sphere of radius $R$: $E = 0$ inside ($r < R$), and $E = \frac{k Q}{r^2}$ outside ($r \ge R$).

EFI inside Non-Conducting Solid Sphere

The electric field at an internal point ($r < R$) of a non-conducting uniformly charged solid sphere of radius $R$, given by $E = \frac{k Q r}{R^3} = \frac{\rho r}{3\varepsilon_0}$.

EFI inside a Spherical Cavity

The uniform electric field produced inside a cavity within a non-conducting solid sphere with volume charge density $\rho$, given by $\mathbf{E} = \frac{\rho \mathbf{a}}{3\varepsilon_0}$, where $\mathbf{a}$ is the vector from the sphere center to the cavity center.

EFI due to Thin Sheet of Charge

The constant electric field intensity produced near an infinitely large thin sheet of surface charge density $\sigma$, given by $E = \frac{\sigma}{2\varepsilon_0}$.

Interaction Potential Energy

The potential energy stored in a system of two point charges separated by distance $r$, given by $U = \frac{k q_1 q_2}{r}$.

Electric Potential ($V$)

The work done per unit positive charge against electrostatic forces in bringing a charge from infinity to a point, given for a point charge by $V = \frac{k Q}{r}$.

Electric Field-Potential Relation

The differential relationship between electric field and potential, given by $d V = -\mathbf{E} \cdot d\mathbf{r}$ or $\mathbf{E} = -\nabla V$, showing that potential decreases in the direction of the electric field.

Equipotential Surface

A surface on which electric potential is equal at every point; it is always perpendicular to electric field lines and cannot intersect other equipotential surfaces.

Internal Potential of Non-Conducting Solid Sphere

The electric potential inside a solid non-conducting sphere at distance $r < R$, given by $V = \frac{k Q (3R^2 - r^2)}{2 R^3}$.

Axial Field of an Electric Dipole

The electric field intensity at distance $r$ along the axial line of a dipole, given by $E = \frac{2 k p}{r^3}$, directed along the dipole moment vector.

Equatorial Field of an Electric Dipole

The electric field intensity at distance $r$ on the equatorial line of a dipole, given by $E = \frac{k p}{r^3}$, directed opposite to the dipole moment vector.

Torque on a Dipole in Uniform EF

The rotational force experienced by a dipole in a uniform electric field, given by $\boldsymbol{\tau} = \mathbf{p} \times \mathbf{E}$ or $\tau = p E \sin(\theta)$.

Potential Energy of a Dipole in EF

The energy stored by a dipole at angle $\theta$ in an electric field, given by $U = -\mathbf{p} \cdot \mathbf{E} = -p E \cos(\theta)$, with a minimum at $\theta = 0^\circ$ (stable equilibrium) and maximum at $\theta = 180^\circ$ (unstable equilibrium).

Concentric Shell Charge Transfer

The electrostatic phenomenon where connecting two concentric conducting shells with a wire causes all charge from the inner shell to transfer entirely to the outer shell.

EFI in Vicinity of a Conductor

The electric field intensity just outside the surface of a charged conductor with surface charge density $\sigma$, given by $E = \frac{\sigma}{\varepsilon_0}$.