Q: A $$2\ \mu\mathrm{C}$$ charge is moved from a point at $$V = 100\ \mathrm{V} to a $$point at $$V = 50\ \mathrm{V}. $$What is the change in electric potential energy?

$$-1.0 \times 10$$^{-4}$$\ \mathrm{J}$$

Q: A $$5\ \mu\mathrm{F}$$ capacitor is charged to $$10\ \mathrm{V}. $$How much energy is stored in the capacitor?

$$2.5 \times 10$$^{-4}$$\ \mathrm{J}$$

Q: A $$1.0\ \mathrm{nC}$$ charge is placed at a point where the electric potential is $$500\ \mathrm{V}. $$What is the electric potential energy of the charge?

$$5.0 \times 10$$^{-7}$$\ \mathrm{J}$$

Question 1

Which of the following best describes the relationship between electric potential energy $$U_{elec}$$ and electric potential $$V$$ for a charge $$q at a $$point in space?

Accepted Answer

$$U_{elec} = qV$$

Question 2

A 9V battery is connected across a parallel-plate capacitor with plate separation $$d = 2\ \mathrm{mm}. $$What is the magnitude of the electric field $$E$$ between the plates?

Accepted Answer

$$E = 4500\ \mathrm{V/m}$$

Question 3

Which of the following statements about conductors in electrostatic equilibrium is FALSE?

Accepted Answer

The electric field just outside the surface is parallel to the surface.

Question 4

A proton is released from rest in a region where the electric potential decreases in the direction of motion. What happens to its kinetic energy?

Accepted Answer

It increases.

Question 5

The energy stored in a capacitor is given by which of the following expressions?

Accepted Answer

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

Question 6

A parallel-plate capacitor has plates of area $$A$$ and separation $$d. $$What is the capacitance $$C of $$this capacitor in vacuum?

Accepted Answer

$$C = \$$varepsilon_0$$ \frac{A}{d}$$

Question 7

If a dielectric with dielectric constant $$\kappa is $$inserted between the plates of a capacitor, what happens to the capacitance?

Accepted Answer

It increases by a factor of $$\kappa.$$

Question 8

The electric potential $$V at a $$distance $$r$$ from a point charge $$q is $$given by:

Accepted Answer

$$V = \frac{1}{4\pi\$$varepsilon_0$$} \frac{q}{r}$$

Question 9

A $$2\ \mu\mathrm{C}$$ charge is moved from a point at $$V = 100\ \mathrm{V} to a $$point at $$V = 50\ \mathrm{V}. $$What is the change in electric potential energy?

Accepted Answer

$$-1.0 	imes 10$$^{-4}$$\ \mathrm{J}$$

Question 10

Which of the following best explains why a 120 V household outlet can be more dangerous than a 10,000 V static shock from touching a doorknob?

Accepted Answer

The household outlet transfers much more charge.

Question 11

The electric field $$E$$ between two parallel plates separated by distance $$d$$ with a potential difference $$\Delta V is$$:

Accepted Answer

$$E = \Delta V / d$$

Question 12

A $$1.5\ \mathrm{V}$$ battery is connected to a parallel-plate capacitor with $$d = 1\ \mathrm{mm}. $$What is the electric field between the plates?

Accepted Answer

$$E = 1500\ \mathrm{V/m}$$

Question 13

Which of the following is TRUE about equipotential surfaces?

Accepted Answer

No work is required to move a charge along an equipotential surface.

Question 14

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

Accepted Answer

It increases by a factor of 2.

Question 15

The energy density $$u_E of $$the electric field in a parallel-plate capacitor is given by:

Accepted Answer

$$u_E = \frac{1}{2} \$$varepsilon_0$$ E^2$

Question 16

A $$5\ \mu\mathrm{F}$$ capacitor is charged to $$10\ \mathrm{V}. $$How much energy is stored in the capacitor?

Accepted Answer

$$2.5 	imes 10$$^{-4}$$\ \mathrm{J}$$

Question 17

Which of the following is the correct expression for the potential difference between two points separated by distance $$d in a $$uniform electric field $$E$$?

Accepted Answer

$$\Delta V = Ed$$

Question 18

A $$1.0\ \mathrm{nC}$$ charge is placed at a point where the electric potential is $$500\ \mathrm{V}. $$What is the electric potential energy of the charge?

Accepted Answer

$$5.0 	imes 10$$^{-7}$$\ \mathrm{J}$$

Question 19

Which of the following is TRUE about the electric potential of a charged conducting sphere of radius $$R$$ and total charge $$Q at a $$distance $$r \u003e R$$ from its center?

Accepted Answer

$$V = \frac{1}{4\pi\$$varepsilon_0$$} \frac{Q}{r}$$

Electric Potential, Potential Energy, and Capacitance: Study Notes for Physics with Calculus

Study Guide - Practice Questions

Study Guide - Flashcards