Question

A capacitor consists of two circular plates of circular plates of radius 5.0 cm separated by a 0.01 mm layer of Teflon (k=2.1). What is the capacitance?

Answer 1

given

d = 0.01 mm

= 0.01 X 10^-3 m

r = 5 cm

= 0.05 m

k = 2.1

$\varepsilon$ _o = 8.85 X 10^-12 F/m

using C = k $\varepsilon$ _o A /d

C = 2.1 X 8.85 X 10^-12 X 3.14 X 0.05² / 0.01 X 10^-3

C = 1.4589 X 10^-8 F

C = 14.589 X 10^-9 F

C = 14.589 nF