Title: Chapter 18.2 Review Capacitance and Potential
1Chapter 18.2 Review Capacitance and Potential
21. A 5 µF capacitor is connected to a 12 volt
battery. What is the potential difference across
the plates of the capacitor when it is fully
charged?
312 volts, a charged capacitor has the same
potential difference across the plates as the
source.
42. What is the charge on one plate of the
capacitor in problem 1 when it is fully charged?
What is the net charge on the capacitor when it
is fully charged?
5q VCq 12 x 5 60 µCorq 12(5 x 10-6) 6
x 10-5 CBut the net charge on a capacitor is
always zero because the and plate have
charges of equal magnitude.
63. How much electrical potential energy is stored
in the capacitor in problem 1?
7PEE ½ CV2PEE ½ 5(12)2PEE 360 µJor,PEE
½ (5x 10-6)(12)2PEE 3.6 x 10-4 J
84. If the plates are separated by a distance of
0.003 m, what is the strength of the electric
field across the plates?
9Ed VE(0.003) 12E 4000 N/C
105. A 9 µF capacitor is connected to a 9 volt
battery. What is the potential difference across
the plates of the capacitor when it is fully
charged?
119 volts, a charged capacitor has the same
potential difference across the plates as the
source.
126. What is the charge on one plate of the
capacitor in problem 5 when it is fully charged?
What is the net charge on the capacitor when it
is fully charged?
13q VCq 9 x 9 81 µCorq 9(9 x 10-6) 8.1
x 10-5 CBut the net charge on a capacitor is
always zero because the and plate have
charges of equal magnitude.
147. How much electrical potential energy is stored
in the capacitor in problem 5?
15PEE ½ CV2PEE ½ 9(9)2PEE 364.5 µJor,PEE
½ (9 x 10-6)(9)2PEE 3.645 x 10-4 J
168. If the plates are separated by a distance of
0.005 m, what is the strength of the electric
field across the plates?
17Ed VE(0.005) 9E 1800 N/C
189. List four ways to increase the charge on a
capacitor.
191. Larger plates2. Plates closer together3.
Different dielectric4. Increase voltage
2010. What is the difference in electrical
potential energy and electric potential?
21Electric potential is electric potential energy
divided by charge.
2211. A proton is moved 0.5 m in the direction of
an electric field with a strength of 5000 N/C.
What is the change in electric potential?
23Ed V5000 x 0.5 V2500 V VMoving in the
direction of the field is a decrease of
potential, so -2500 V V.
2412. What is the change in electrical potential
energy of the proton in problem 11?
25PEE qVPEE (1.6 x 10-19)(2500)PEE -4 x
10-16 J
2613. An electron is moved 0.8 m in the direction
of an electric field with a strength of 3000 N/C.
What is the change in electric potential?
27Ed V3000 x 0.8 V2400 V VMoving in the
direction of the field is a decrease of
potential, so -2400 V V.
2814. What is the change in electrical potential
energy of the electron in problem 13?
29PEE qVPEE (-1.6 x 10-19)(-2400)PEE 3.88
x 10-16 JThe electron is being moved in the
direction it does not want to go. That is an
increase in potential energy.
3015. A helium nucleus (composed of two protons and
two neutrons) is moved 24 cm in the direction of
an electric field with a strength of 9000 N/C.
What is the change in electric potential?
31Ed V9000 x 0.24 V2160 V VMoving in the
direction of the field is a decrease of
potential, so -2160 V V.
3216. What is the change in electrical potential
energy of the helium nucleus in problem 15?
33PEE qVPEE (1.6 x 10-19)(2)(-2160)(There
are two protons in one helium nucleus.)PEE
-6.912 x 10-16
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