Question

In order to make the foam fuzzy die hanging from his rearview mirror shinier, Paul staples two thin pieces of aluminum foil on opposite faces of the die, completely covering the two faces. It is a perfect cube with a single side of 5cm, and is filled with Polyfil which his a dielectric constant of 3.8. Find the capacitance of the shiny fuzzy die.

Answer 1

given

we have _o = 8,85 X 10^-12 F/m

dielectric constant of 3.8 = k

it is a cube of side is 5 cm = 0.05 m = a

it means that the at the faces of a die so d = 0.05 m

A = area of the cube = 6 a² = 6 X 0.05²

capacitance C = ?

so the capacitance equation is C = k _o A / d

C = 3.8 X 8.85 X 10^-12 X 6 X 0.05² / 0.05

C = 1.0089 X 10^-11 F

C = 10.089 X 10^-12 F

or

C = 10.089 pF