An air capacitor has its plates separated by a 0.1 cm distance. The total area of the plates is 10 cm². Identify the value of capacitor from the options given below.

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ALP CBT 2 Electronic Mechanic Previous Paper: Held on 21 Jan 2019 Shift 1

Answer 1

Concept:

The capacitance of a parallel plate capacitor is given by:

\(C = \frac{{ϵ A}}{d}\)

Where ϵ is the dielectric constant. For air, the value of ϵ is:

ϵ = 8.854 × 10^-14 C²/N-cm²

A is the area of the cross-section of the plates

d is the distance between the plates

Calculation:

With d = 0.1 cm, A = 10 cm², and ϵ = 8.854 × 10^-14 C²/N-cm², the value of capacitance will be:

\(C = \frac{{8.854× 10^{-14}× 10}}{0.1}\)

C = 8.854 × 10^-12 F

C = 8.85 pF