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Free Practice Quiz Question List

2 Electric Potential and Capacitance Online Quiz Questions

Use this free practice quiz with 20 questions to review 2 Electric Potential and Capacitance, test your knowledge, and prepare for your next test or exam.

20 questions
01
True or false
1 point

True or false: In electrostatic equilibrium, the surface and interior of a conductor are at the same electric potential.

  1. A

    True

  2. B

    False

02
True or false
1 point

True or false: In a uniform electric field in vacuum, doubling the field strength makes the energy density four times as large.

  1. A

    True

  2. B

    False

03
Choose one
1 point

An empty cavity lies inside a conductor in electrostatic equilibrium, and no charge is placed in the cavity. What is the electric field inside the cavity?

  1. A

    The field in the cavity is uniform and nonzero.

  2. B

    The field in the cavity is zero.

  3. C

    The field in the cavity points toward the nearest cavity wall.

  4. D

    The field in the cavity depends only on the conductor's total charge.

04
Choose one
1 point

A point charge of +3.0 nC+3.0\ \mathrm{nC} is 0.30 m0.30\ \mathrm m from a point. Using k=9.0×109 N m2/C2k=9.0\times10^9\ \mathrm{N\,m^2/C^2}, what is the electric potential at that point relative to infinity?

  1. A

    9.0 V

  2. B

    30 V

  3. C

    90 V

  4. D

    270 V

05
Written response
1 point

What property of a capacitor measures the amount of charge stored per unit potential difference?

06
Choose one
1 point

A +2.0 μC+2.0\ \mu\mathrm C charge moves through a potential difference of −5.0 V-5.0\ \mathrm V. What is its change in electric potential energy?

  1. A

    +1.0×10−5 J+1.0\times10^{-5}\ \mathrm J

  2. B

    −1.0×10−5 J-1.0\times10^{-5}\ \mathrm J

  3. C

    +2.5×10−6 J+2.5\times10^{-6}\ \mathrm J

  4. D

    −2.5×10−6 J-2.5\times10^{-6}\ \mathrm J

07
Written response
1 point

A capacitor has capacitance 2.0 μF2.0\ \mu\mathrm F and potential difference 3.0 V3.0\ \mathrm V. Calculate its stored energy in joules.

08
True or false
1 point

True or false: For a uniform electric field in vacuum, the field energy density is proportional to the square of the field strength.

  1. A

    True

  2. B

    False

09
Choose one
1 point

An ideal parallel-plate capacitor has its plate area doubled while the plate separation is halved. By what factor does its capacitance change, assuming no dielectric is present and edge effects remain small?

  1. A

    It becomes half as large.

  2. B

    It doubles.

  3. C

    It becomes four times as large.

  4. D

    It becomes eight times as large.

10
Choose all
1 point

A dielectric is fully inserted into a disconnected capacitor. Select all statements that correctly describe what happens to the capacitor.

  1. A

    The magnitude of the charge remains constant.

  2. B

    The potential difference decreases.

  3. C

    The stored energy increases.

  4. D

    The stored energy decreases.

11
Choose all
1 point

A capacitor remains connected to a battery while a dielectric is fully inserted. Select all statements that correctly describe what happens to the capacitor.

  1. A

    The potential difference remains constant.

  2. B

    The capacitor's charge increases.

  3. C

    The capacitor's capacitance decreases.

  4. D

    The stored energy increases.

12
Open ended
1 point

Explain how polarization in a dielectric changes the electric field inside a capacitor and why inserting the dielectric increases capacitance. In your explanation, connect the change in field to the definition of capacitance.

13
Choose one
1 point

A parallel-plate capacitor has negligible edge effects. If its plate area is doubled while the plate separation and the space between the plates remain unchanged, how does its capacitance change?

  1. A

    It becomes half as large.

  2. B

    It becomes twice as large.

  3. C

    It stays the same.

  4. D

    It becomes four times as large.

14
Choose one
1 point

Why can a sharp region on a conductor have a particularly strong electric field just outside its surface?

  1. A

    The conductor's interior field becomes nonzero there.

  2. B

    The conductor has lower capacitance there because charge cannot reside on the surface.

  3. C

    Surface charge is more concentrated there, producing a stronger nearby field.

  4. D

    The potential at the sharp region must be different from the potential elsewhere on the conductor.

15
Choose one
1 point

At a point, two point charges contribute electric potentials of +8 V+8\ \mathrm{V} and −3 V-3\ \mathrm{V}. What is the total electric potential at that point?

  1. A

    −11 V-11\ \mathrm{V}

  2. B

    +5 V+5\ \mathrm{V}

  3. C

    +11 V+11\ \mathrm{V}

  4. D

    −5 V-5\ \mathrm{V}

16
Choose one
1 point

A uniform electric field of 250 V/m250\ \mathrm{V/m} points from point A to point B, which is 0.40 m0.40\ \mathrm{m} away along the field. What is the potential difference VB−VAV_B-V_A?

  1. A

    −100 V-100\ \mathrm{V}

  2. B

    −62.5 V-62.5\ \mathrm{V}

  3. C

    +100 V+100\ \mathrm{V}

  4. D

    +62.5 V+62.5\ \mathrm{V}

17
Written response
1 point

A capacitor carries charge magnitude 15 μC15\ \mu\mathrm{C} when the potential difference across it is 5 V5\ \mathrm{V}. What is its capacitance? Enter the value in μF\mu\mathrm{F}.

18
Written response
1 point

A charge of −3 μC-3\ \mu\mathrm{C} moves through a potential difference of +2 V+2\ \mathrm{V}. What is its signed change in electric potential energy? Enter the value in μJ\mu\mathrm{J}.

19
Fill in the blank
1 point

For a conductor in electrostatic equilibrium, any excess charge resides . Just outside the conductor, the electric field points to its surface.

20
Fill in the blank
1 point

The potential at point A is 8 V and at point B is 3 V. If the chosen zero of potential changes so that 10 V is added to the potential at every point, the potential difference between A and B remains .