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Electrical Engineering

Electric Power (Voltage and Resistance)

For an ohmic resistor, dissipation grows with squared applied voltage and decreases with resistance at fixed voltage.

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Source & review

Difficulty

Intermediate

Read time

5 min

Prerequisites

Basic algebra, consistent units, and the stated model assumptions

Review statusNeeds review

Source

OpenStax, College Physics 2e, §20.5 (Paul Peter Urone and Roger Hinrichs)

OpenFormulaGraph equation reference; FormuLab adaptation details and license are provided below.

Adapted from OpenFormulaGraph, under CC BY 4.0.

FormuLab adapted wording, notation, applicability conditions and topic placement, and expanded the numerical check into a worked example.

Definition
Understanding the core concept

For an ohmic resistor, dissipation grows with squared applied voltage and decreases with resistance at fixed voltage. This form combines the electrical power relation with Ohm’s law.

Variables & Units
Understanding each component
SymbolMeaningUnits
Power
Voltage
Electrical Resistance
Real-World Applications
Where this formula is used in practice

Resistor heating

Estimate electrical dissipation from voltage.

Voltage changes

Compare resistive power at different applied voltages.

Worked Example
Step-by-step calculation with real numbers

Problem

A 5.00 Ω resistor has a steady 10.0 V across it. Find its dissipated power.

Given

Solution

1
2
3

Final Answer

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