Question 1

A parallel-plate capacitor is connected to a battery of voltage $$V. If $$the distance between the plates is doubled while keeping the area constant, what happens to the capacitance?

Accepted Answer

It is halved.

Question 2

Which of the following best describes an equipotential surface?

Accepted Answer

A surface where the electric potential is constant everywhere.

Question 3

A proton is released from rest in a uniform electric field. Which of the following statements is true about its motion?

Accepted Answer

It moves toward higher electric potential.

Question 4

The energy stored in a capacitor is given by $$U = \frac{1}{2}CV^2$. If the voltage across the capacitor is tripled, by what factor does the stored energy increase?

Accepted Answer

By a factor of 9.

Question 5

Which equation correctly relates the electric field $$E to $$the potential difference $$V_{ba}$$ and distance $$d$$ between two parallel plates?

Accepted Answer

$$E = -\frac{V_{ba}}{d}$$

Question 6

A 5.0 $$	ext{μF}$$ capacitor is charged to 12 V. How much energy is stored in the capacitor?

Accepted Answer

$$3.6 	imes 10$$^{-3}$$ J

Question 7

Which of the following statements about dielectrics is correct?

Accepted Answer

A dielectric increases the capacitance of a capacitor.

Question 8

The potential at a distance $$r$$ from a point charge $$Q is $$given by $$V = k \frac{Q}{r}. If $$the distance is doubled, what happens to the potential?

Accepted Answer

It is reduced to half its original value.

Question 9

A charged particle moves from point $$a to $$point $$b in an $$electric field. The work done by the electric field is $$W = -q(V_b - V_a). If$$ $$V_b \u003e V_a$$ and $$q is $$positive, what is the sign of the work?

Accepted Answer

Negative

Question 10

Which of the following is the correct unit for electric potential?

Accepted Answer

Volt (V)

Question 11

An electron is accelerated from rest through a potential difference of 1000 V. What is its final kinetic energy in electron volts (eV)?

Accepted Answer

1000 eV

Question 12

Which of the following best describes the relationship between electric field lines and equipotential lines?

Accepted Answer

Electric field lines are perpendicular to equipotential lines.

Question 13

A capacitor is filled with a dielectric material of constant $$K. $$How does the capacitance change compared to when the capacitor is filled with air?

Accepted Answer

It increases by a factor of $$K.$$

Question 14

The energy density in an electric field is given by $$u = \frac{1}{2}\$$epsilon_0$$ E^2$. What does this expression represent?

Accepted Answer

The energy stored per unit volume.

Question 15

A cathode ray tube (CRT) in a television uses electric fields to steer electrons. What is the primary function of the vertical and horizontal deflection plates?

Accepted Answer

To change the direction of the electron beam.

Question 16

Which of the following is true about the surface of a conductor in electrostatic equilibrium?

Accepted Answer

It is an equipotential surface.

Question 17

A parallel-plate capacitor has plates of area $$A$$ separated by distance $$d. $$What is the formula for its capacitance?

Accepted Answer

$$C = \frac{\$$epsilon_0$$ A}{d}$$

Question 18

An ECG (electrocardiogram) detects heart defects by measuring:

Accepted Answer

Changes in electric potential on the surface of the heart.

Question 19

The potential due to an electric dipole at a point far from the dipole is given by $$V = k \frac{p \cos 	heta}{r^2$}. $$What does $$p$$ represent?

Accepted Answer

The dipole moment.

Question 20

If a capacitor is suddenly discharged, what real-world effect can this have?

Accepted Answer

It can cause a dangerous electric shock.

Electric Potential and Capacitance: Study Notes for College Physics

Study Guide - Practice Questions

Study Guide - Flashcards