SP212/3321&5521
Chapter 25 - Worksheet #3
Question 1: A parallel plate capacitor consists of two square metallic plates, each of which is 2.40 cm
long on a side, that are separated by 3.20 mm. A material with dielectric constant κ=4.50 fills the
space between the two plates. The capacitor is fully charged by a 24.0 V battery. (a) What is the
capacitance of the capacitor? (b) How much energy is stored in the capacitor? (c) What is the
magnitude of the electric field between the capacitor plates? (d) What is the energy density of the
electric field between the plates?
Question 2: A parallel plate capacitor consists of two square metallic plates, each of which is 0.015 m
long on a side, that are separated by 0.0045 m. The left half of the capacitor is filled by a material
with a dielectric constant of κ=4.5 while the right half is filled by a material with a dielectric
constant of κ=1.5. (a) What is the capacitance of this device? [Hint: Treat each half as a separate
capacitor. These two capacitors are then in parallel.] (b) How much charge will this capacitor hold
if the electric field between the plates has a magnitude of 1.2×104 N/C?
κ=4.5 κ=1.5
SP212/3321&5521
Chapter 25 - Worksheet #3
Question 3: A parallel plate capacitor consists of two circular metallic plates, each with radius
0.035 m, that are separated by 0.0060 m. The top half of the capacitor is filled by a material with a
dielectric constant of κ=3.8 while the bottom half is filled by a material with a dielectric constant
of κ=1.4. (a) What is the capacitance of this device? [Hint: Treat each half as a separate capacitor.
These two capacitors are then in series.] (b) How much energy will this capacitor store if it is
charged by a 36 V battery.
κ=3.8
κ=1.4