Question

A parallel-plate capacitor made of half-circular plates of radius 10 cm separated by 1.50 mm is charged to a potential difference of 600 volts by a battery. Then a sheet of tantalum pentoxide is pushed between the plates, completely filling the gap between them. How much additional charge flows from the battery to one of the plates when the tantalum pentoxide is inserted? Dielectric constant for some materials: mylar 3.1 polyethylene 2.6 polyvinyldifluoride 11. tantalum pentoxide 25. Teflon 2.1

Answer 1

given d =1.5 mm = 1.5 X 10^-3 m

r = 10 cm

= 0.1 m

V = 600 volts

A = 3.14 X 0.1²

using C = k _o A / d

then can write C₁ = _o A / d

and

C = 3.1 _o A / d

we have charge q = C V

so using above equations

dq = (_o A / d) ( 3.1 - 1 ) X V

= 8.85 X 10^-12 X 3.14 X 0.1² X 2.1 X 600 / 1. 5 X 10^-3

dq = 1.11 X 10^-7 C