# A parallel-plate capacitor with air dielectric has a capacitance of 12 pF...?

What is the capacitance of a capacitor that has the following:

a) The same separation and dielectric but five times the plate area?

b) The same dielectric but four times the area and one-fifth the plate spacing?

c) A dry paper dielectric, six times the plate area and twice the plate spacing? (Dry paper has a dielectric constant 2.2 times larger than air.)

### 3 Answers

- billrussell42Lv 77 years agoFavorite Answer
a) times 5

b) x 4 x 5

c) x 2.2 x 6 x (1/2)

Parallel plate cap

C = ε₀εᵣ(A/d) in Farads

ε₀ is vacuum permittivity, 8.854e-12 F/m

εᵣ is dielectric constant or relative permittivity

of the material (vacuum = 1)

A and d are area of plate in m² and separation in m

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- Randy PLv 77 years ago
Capacitance is proportional to area, proportional to dielectric constant, and inversely proportional to separation.

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- RickLv 77 years ago
C=eo er Area/distance. Use this equation to answer all of your questions.

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