An ideal vacuum parallel-plate capacitor has capacitance proportional to plate area and inversely proportional to plate separation.
Difficulty
Intermediate
Read time
5 min
Prerequisites
Basic algebra, consistent units, and the stated model assumptions
Source
OpenStax, College Physics 2e, §19.5 (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.
An ideal vacuum parallel-plate capacitor has capacitance proportional to plate area and inversely proportional to plate separation. A dielectric changes the permittivity and therefore the capacitance.
| Symbol | Meaning | Units |
|---|---|---|
| Capacitance | ||
| Permittivity of Free Space | ||
| Area | ||
| Length (plate separation) |
Estimate capacitance from plate dimensions.
Compare capacitance at different gaps.
Find the capacitance of vacuum plates with area 0.0100 m² and separation 0.00100 m.
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.
Assumptions
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