Chapter 17: Electric Potential and Electric Energy; Capacitance
Practice Questions



1.  

Which of the following is not a unit for the Electric Field?

N/C
V/m
V/C
J/Cm


2.  

A 9 volt transistor battery has

more energy available than a 6 volt lantern battery.
more energy available than a 1/1/2 volt flashlight battery.
more energy available per charge moved than a 6 volt lant
all of the above.
none of the above.


3.  

The unit of capacitance is the

faraday.
farad.
Joule.
Volt.


4.  

The unit for the dielectric constant is

Cm
J/C
V/m
None of the above.


5.  

A farad is

C/V
V/C
N/m
CV


6.  

A capacitor has circular plates of radius 10 cm separated by 1 mm. Its capacitance is

8.85x10-12 F
2.78x10-13 F
1.11x10-9 F
2.78x10-10 F


7.  

A capacitor has circular plates of radius 10 cm separated by 1 mm. If the capacitor is connected to a 12 volt battery, the charge on the capacitor will be

3.34x10-9 C
2.5x10-12 C
1x10-6 C
12x10-12 C


8.  

What is the electric field in the capacitor in the previous question?

12 N/C
.012 N/C
12000 N/C
120 N/C


9.  

What would be the energy stored in the capacitor in the previous question?

0.02 microJ
1.7 nanoJ
4x10-8 J
3.1 mJ


10.  

A dielectric is inserted into the capacitor in the previous question and the stored energy is found to be 0.14 microJ, the dielectric is

air.
water.
alcohol.
Mica.


11.  

Capacitor 1 has capacitance C1 and voltage V1. Capacitor 2 has twice the capacitance and the same voltage. Its energy U2 equals

2U1
4U1
U1
6U1


12.  

Capacitor 1 has capacitance C1 and voltage V1. Capacitor 2 has twice the voltage and the same capacitance. Its energy U2 equals

2U1
4U1
U1
6U1


13.  

Two capacitors have the same capacitance but the second has twice the charge of the first. Its stored energy is

equal to twice that of the first.
equal to four times that of the first.
equal to the energy of the first one.
equal to eight times that of the first.


14.  

The second of two capacitors has twice the charge and half the voltage. Its energy is

twice that of the first.
four times that of the first.
equal to that of the first one.
six times that of the first.


15.  

The second of two capacitors has twice the charge and half the voltage. The capacitance of the second is

equal to that of the first.
twice that of the first.
four times that of the first.
one-fourth that of the first.


16.  

A proton is accelerated from rest through a potential of 500 volts. Its final kinetic energy is

50 eV.
500 eV.
1000 eV.
2000 eV.


17.  

What is the final velocity of the proton in the previous problem? (The mass of the proton is 1.67x10-27 kg)

8x1014 m/s
1000 m/s
3x108 m/s
3x105 m/s


18.  

An alpha particle (Q=+2e) is accelerated from rest through a potential difference of 500 volts. Its final kinetic energy is

50 eV
500 eV
1000 eV
2000 eV


19.  

Two alpha particles are placed near each other so that each experiences a potential of 500 volts. They are allowed to fly far apart. What is the final potential of each?

zero.
500 volts.
-500 volts.
250 volts.


20.  

What is the final kinetic energy of each alpha particle in the previous question?

500 eV
1000 eV
2000 eV
zero


21.  

If Q1 and Q2 are equal and oppositely charged, what is the potential at point B?

zero
negative
positive
Cannot be determined.


22.  

In the previous question the work required to move a positive charge from A to B is

zero.
positive.
negative.
Cannot be determined.


23.  

If both charges in the figure are positive and the potential at B is 500 volts, what is the potential at A, 3 meters above the point B?

0 volts.
250 volts.
400 volts.
500 volts.


24.  

If Q1 in the above figure is twice Q2 and both are positive, where can a point of zero potential be found?

Between the two charges.
To the right of Q2.
To the left of Q2.
At no finite distance from Q2 .


25.  

In the previous question if Q1 is negative and twice Q2 which is positive where will the potential be zero?

3.33 m to the left of Q1.
3.33 m to the right of Q1.
3.33 m to the left of Q2.
3.33 m to the right of Q2.


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