Question

A student working in the physics laboratory connects a parallel-plate capacitor to a battery, so that the potential difference between the plates is 225 V. Assume a plate separation of d = 1.27 cm and a plate area of A = 25.0 cm². When the battery is removed, the capacitor is plunged into a container of distilled water. Assume distilled water is an insulator with a dielectric constant of 80.0.

(a) Calculate the charge on the plates (in pC) before and after the capacitor is submerged. (Enter the magnitudes.)

before Q_i = ___ pC

after Q_f = ___ pC

(b)

Determine the capacitance (in F) and potential difference (in V) after immersion.

C_f = ___ F

ΔV_f = ___ V

(c) Determine the change in energy (in nJ) of the capacitor.

ΔU = ___ nJ

(d)

What If? Repeat parts (a) through (c) of the problem in the case that the capacitor is immersed in distilled water while still connected to the 225 V potential difference.

Calculate the charge on the plates (in pC) before and after the capacitor is submerged. (Enter the magnitudes.)

before Q_i = ___ pC

after Q_f = ___ pC

Determine the capacitance (in F) and potential difference (in V) after immersion.

C_f = ___ F

ΔV_f = ___ V

Determine the change in energy (in nJ) of the capacitor.

ΔU = ___ nJ

Answer 1