Ohm's Law and Electrical Resistance

A set of 10 vocabulary flashcards reviewing the concepts, definitions, equations, and experimental setups related to Ohm's Law and electrical resistance.

Georg Simon Ohm

The German physicist (1789–1854) who first proved the proportional relationship between current and voltage ($I \propto V$) and created analogies comparing current to water flow, voltage to water height difference, and resistance to pipe thickness.

Ohm's Law

The principle stating that the electrical current $I$ flowing through a conductor is directly proportional to the applied voltage $V$ ($I \propto V$), meaning the conductor's resistance $R$ remains constant regardless of the voltage.

Definition Equation for Electrical Resistance

$R = \frac{V}{I}$, defined as the ratio of applied voltage $V$ to current $I$ across a conductor; this equation defines resistance for all electrical devices regardless of whether they follow Ohm's Law.

Ohm (\Omega)

The SI unit of electrical resistance, defined as $1\,\Omega = 1\,\text{V/A}$.

Ohmic Material

A substance (such as copper or most metals under appropriate electric fields) that obeys Ohm's Law, maintaining a constant resistance $R$ such that its current-voltage graph is a straight line passing through the origin.

Nonohmic Material

A substance or component (such as a miniature bulb, germanium diode, or silicon diode) whose resistance changes with current $I$, resulting in a non-linear relationship between voltage and current.

Hooke's Law Comparison

An analogy illustrating that Ohm's Law is not a universal physics conservation law; like Hooke's Law which fails beyond an elastic limit, Ohmic materials deviate from Ohm's Law when subjected to excessively large voltages or electric fields.

Activity 2 Apparatus

The equipment specified for testing nonohmic circuit behavior, consisting of a DC power supply, digital multimeter, $6\,\text{V}$ miniature light bulb, germanium diode, silicon diode, and graph paper.

Circuit Diagram for Ohm's Law Measurement

A schematic diagram showing a DC power supply with $(+)$ and $(-)$ terminals, an ammeter $A$ connected in series, and a voltmeter $V$ connected in parallel across a resistor.

Color-Coded Resistors

Resistors (labeled A, B, and C) marked with distinct color bands used in Activity 1 to demonstrate linear Ohmic behavior under applied voltages up to $10\,\text{V}$.