Question 1

Which of the following statements best describes the conservation of electric charge?

Accepted Answer

The total electric charge of the universe is a constant; charge is conserved in all processes.

Question 2

A glass rod is rubbed with silk, and the rod becomes positively charged. What happens at the atomic level?

Accepted Answer

Electrons are transferred from the glass rod to the silk.

Question 3

Which of the following materials is most likely to be a good conductor of electricity?

Accepted Answer

Copper

Question 4

According to Coulomb’s Law, what is the force between two point charges $$q_1$$ and $$q_2$$ separated by a distance $$r in $$vacuum?

Accepted Answer

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

Question 5

A neutral metal sphere is brought near a negatively charged rod. What happens to the charges in the sphere?

Accepted Answer

Negative charges in the sphere move away from the rod, leaving the near side positively charged.

Question 6

Which of the following best describes the direction of the electric field created by a positive point charge?

Accepted Answer

It points radially outward away from the charge.

Question 7

If a conductor is in electrostatic equilibrium, what is the electric field inside the conductor?

Accepted Answer

It is zero.

Question 8

Which of the following statements about electric field lines is correct?

Accepted Answer

Electric field lines start on positive charges and end on negative charges.

Question 9

A parallel-plate capacitor consists of two large, flat, conducting plates with equal and opposite charges. What is the direction of the electric field between the plates?

Accepted Answer

From the positively charged plate to the negatively charged plate.

Question 10

Which of the following is the correct expression for the electric field $$E$$ due to a point charge $$q at a $$distance $$r$$?

Accepted Answer

$$E = k_e \frac{q}{r^2$}$$

Question 11

A charged rod is brought near, but does not touch, a neutral metal sphere. The sphere is then grounded while the rod is still nearby, and finally the ground connection is removed before the rod is taken away. What is the final charge on the sphere?

Accepted Answer

It has a charge opposite in sign to that of the rod.

Question 12

Which of the following best describes Gauss’s Law?

Accepted Answer

The electric flux through a closed surface is proportional to the charge enclosed by the surface.

Question 13

A small test charge $$q_0 is $$placed in an electric field $$E. $$What is the force $$F$$ experienced by the test charge?

Accepted Answer

$$F = q_0$ E$$

Question 14

Which of the following is a property of semiconductors?

Accepted Answer

Their conductivity can change with chemical composition or exposure to light.

Question 15

If three point charges are placed at the corners of an equilateral triangle, how is the net force on one charge determined?

Accepted Answer

By vector addition of the forces from the other two charges (superposition principle).

Question 16

Which of the following statements about the distribution of excess charge on a conductor is correct?

Accepted Answer

Excess charge resides only on the surface of the conductor.

Question 17

A charged balloon sticks to a neutral wall. What is the best explanation for this phenomenon?

Accepted Answer

The wall becomes polarized, and opposite charges are attracted to the balloon.

Question 18

Which of the following is the correct expression for electric flux $$\Phi_E$$ through a surface with electric field $$E$$ perpendicular to area $$A$$?

Accepted Answer

$$\Phi_E = E \cdot A$$

Question 19

Which of the following is NOT a property of electric field lines?

Accepted Answer

They form closed loops around isolated charges.

Question 20

A spherical conductor is given a net positive charge. Where is the electric field strongest?

Accepted Answer

At points on the surface where the curvature is greatest.

Electric Charges, Forces, and Fields – Chapter 19 Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard