Electricity & Magnetism

Flashcards covering formulas, Ohm's law representations, and Kirchhoff's circuit laws.

Current Density ($J$)

The electric current per unit area, expressed as $J = \frac{I}{A} = v\,e\,n$.

Resistance ($R$)

The opposition to current flow in a conductor, given by $R = \frac{\rho l}{A}$.

Vector Form of Ohm's Law

The fundamental relationship expressed as $\vec{E} = \rho \vec{J}$ and $\vec{J} = \sigma \vec{E}$.

Temperature Coefficient of Resistance ($\alpha$)

The measure of change in electrical resistance with temperature, defined as $\alpha = \frac{R_2 - R_1}{R_1 (\theta_2 - \theta_1)}$.

Heat Energy ($H$)

The electrical heat energy generated over time $t$, calculated as $H = I^2 R t$.

Electric Power ($P$)

The rate of electrical energy transfer in a circuit, given by $P = I^2 R = V I = \frac{V^2}{R}$.

Scope of Ohm's Law

Ohm's law is used for simple current circuits.

Kirchhoff's Current Law (KCL) / Junction Law

A fundamental circuit rule that depends on the principle of conservation of charge.

Statement of Kirchhoff's Current Law

The algebraic sum of the currents meeting at a point is zero.

Kirchhoff's Voltage Law (KVL) / Loop Law

A fundamental rule for circuit loop analysis, also known as the loop law.