Question 1

Which of the following best describes the difference between conductors and insulators?

Accepted Answer

Conductors are materials through or along which charges easily move, while insulators are materials in or on which charges are immobile.

Question 2

A glass rod is rubbed with a silk cloth and brought near two rods: one red and one clear. The glass rod attracts both rods. What does this observation suggest about the types of charge?

Accepted Answer

There are more than two types of charge.

Question 3

Which of the following statements about the conservation of charge is correct?

Accepted Answer

The total amount of charge in a closed system remains constant.

Question 4

A negatively charged rod is brought close to a metal electroscope (without touching). The vane moves. What is the best explanation for this observation?

Accepted Answer

Charge polarization occurs, causing electrons in the electroscope to move away from the rod.

Question 5

Which of the following is the correct expression for the magnitude of the electrostatic force between two point charges $$q_1$$ and $$q_2$$ separated by a distance $$r$$?

Accepted Answer

$$F = k \frac{q_1$ q_2$}{r^2$}$$

Question 6

A plastic comb is charged by rubbing it with wool. What is the most likely process responsible for the comb becoming charged?

Accepted Answer

Electrons are transferred from the wool to the comb.

Question 7

If a positively charged object is brought near a neutral metal sphere, what happens to the charges in the sphere?

Accepted Answer

Electrons in the sphere are attracted toward the side near the charged object.

Question 8

Which of the following best explains why packing peanuts stick to your clothes after opening a package?

Accepted Answer

Packing peanuts become charged and attract neutral objects by polarization.

Question 9

A neutral electroscope is touched by a negatively charged rod. What is the final charge on the electroscope after the rod is removed?

Accepted Answer

The electroscope becomes negatively charged.

Question 10

Which of the following is true about the force between two charges according to Coulomb's law?

Accepted Answer

The force decreases as the distance between the charges increases.

Question 11

A negatively charged rod is brought near a wooden (insulating) rod. What is the most likely observation?

Accepted Answer

The wooden rod is attracted due to polarization.

Question 12

Which of the following best describes the process of charging by induction?

Accepted Answer

A charged object is brought near a conductor, and the conductor is then grounded, resulting in a net charge on the conductor.

Question 13

Which of the following is the value of the fundamental charge $$e$$?

Accepted Answer

$$1.60 	imes 10$$^{-19}$$\ \mathrm{C}$$

Question 14

A neutral atom becomes a positive ion when:

Accepted Answer

It loses an electron.

Question 15

Which of the following is true about the charges on quarks?

Accepted Answer

Quarks have charges that are fractions of $$e$$, such as $$+\frac{2}{3}e or$$ $$-\frac{1}{3}e.$$

Question 16

If two point charges $$q_1$$ and $$q_2$$ are separated by a distance $$r$$, and both charges are doubled, what happens to the magnitude of the force between them?

Accepted Answer

The force is quadrupled.

Question 17

A student touches a positively charged electroscope with their finger. What happens to the amount of excess charge on the electroscope?

Accepted Answer

The amount of excess charge decreases.

Question 18

Which of the following best describes charge polarization?

Accepted Answer

A slight separation of positive and negative charges in a neutral object.

Question 19

In a demonstration, a negatively charged rod is brought near a metal rod with zero net charge. The metal rod is attracted to the charged rod. What is the best explanation?

Accepted Answer

Charge polarization causes the side of the metal rod near the charged rod to become positively charged.

Question 20

Which of the following is a correct statement about the direction of the electric force between two point charges?

Accepted Answer

The force is attractive for opposite charges and repulsive for like charges.

Introduction to Electric Charges and Forces (Ch. 22): Study Notes for College Physics

Study Guide - Practice Questions

Study Guide - Flashcards