Question 1

A point charge $$q is $$placed at a distance $$r$$ from another point charge $$Q. $$What is the magnitude of the electric force between them?

Accepted Answer

$$F = k_e \frac{qQ}{r^2$}$$

Question 2

Which of the following best describes the electric field inside a conductor in electrostatic equilibrium?

Accepted Answer

The electric field inside is always zero.

Question 3

A parallel-plate capacitor has plates of area $$A$$ separated by distance $$d$$ and filled with a dielectric of constant $$\varepsilon. $$What is its capacitance?

Accepted Answer

$$C = \varepsilon \frac{A}{d}$$

Question 4

A charged particle $$q$$ moves through a uniform electric field $$E$$ over a distance $$d. $$What is the change in electric potential energy?

Accepted Answer

$$\Delta U = -qEd$$

Question 5

What is the electric field just outside the surface of a conductor with surface charge density $$\sigma$$?

Accepted Answer

$$E = \frac{\sigma}{\$$varepsilon_0$$}$$

Question 6

Which of the following statements about the electric potential due to multiple point charges is correct?

Accepted Answer

The net electric potential is the sum of the potentials due to each charge.

Question 7

A uniformly charged sphere of radius $$R$$ has total charge $$Q. $$What is the electric field at a distance $$r \u003c R$$ from the center?

Accepted Answer

$$E = \frac{1}{4\pi\$$varepsilon_0$$} \frac{Qr}{R^3$}$$

Question 8

What is the energy stored in a capacitor of capacitance $$C$$ charged to a potential $$V$$?

Accepted Answer

$$U = \frac{1}{2}CV^2$

Question 9

A charged particle $$q is $$placed in a uniform electric field $$E. $$What is the force on the particle?

Accepted Answer

$$F = qE$$

Question 10

Two point charges $$q_1$$ and $$q_2$$ are separated by a distance $$r. $$What is the potential energy of the system?

Accepted Answer

$$U = \frac{1}{4\pi\$$varepsilon_0$$} \frac{q_1q_2}{r}$$

Question 11

An infinite sheet with surface charge density $$\sigma$$ produces an electric field of what magnitude?

Accepted Answer

$$E = \frac{\sigma}{2\$$varepsilon_0$$}$$

Question 12

A parallel-plate capacitor is connected to a battery and then disconnected. If the plates are pulled apart, what happens to the stored energy?

Accepted Answer

The stored energy increases.

Question 13

Which of the following is true about the direction of the electric field between two oppositely charged parallel plates?

Accepted Answer

It points from the positive plate to the negative plate.

Question 14

If the electric potential at point A is $$V_A$$ and at point B is $$V_B$$, what is the work done by the electric field in moving a charge $$q$$ from A to B?

Accepted Answer

$$W = q(V_A - V_B)$$

Question 15

A point charge $$q is $$moved from infinity to a distance $$r$$ from another point charge $$Q. $$What is the change in electric potential energy?

Accepted Answer

$$\Delta U = \frac{1}{4\pi\$$varepsilon_0$$} \frac{qQ}{r}$$

Question 16

Which of the following is a correct statement about the properties of conductors in electrostatic equilibrium?

Accepted Answer

The electric field inside a conductor is zero.

Question 17

A capacitor is charged to a voltage $$V$$ and then disconnected from the battery. If the plate separation is doubled, what happens to the capacitance?

Accepted Answer

The capacitance is halved.

Question 18

Which of the following best describes the meaning of electric potential?

Accepted Answer

Electric potential is the potential energy per unit charge.

Question 19

A charged particle is released from rest in a uniform electric field. What type of motion does it undergo?

Accepted Answer

Constant acceleration in the direction of the field.

Question 20

If two point charges of equal magnitude but opposite sign are placed a distance $$d$$ apart, what is the electric field at the midpoint between them?

Accepted Answer

$$E = \frac{1}{4\pi\$$varepsilon_0$$} \frac{4q}{d^2$}$$

Electric Fields, Potentials, and Capacitance: Exam 1 Review Notes

Study Guide - Practice Questions

Study Guide - Flashcards