Question 1

Which of the following best describes the process by which a plastic comb becomes charged after being rubbed against dry hair?

Accepted Answer

The comb gains electrons from the hair.

Question 2

Which statement about conductors and insulators is correct?

Accepted Answer

Conductors have free electrons that can move throughout the material.

Question 3

A negatively charged rod is brought near (but does not touch) a neutral metal sphere. What happens to the charges in the sphere?

Accepted Answer

Electrons in the sphere move away from the rod.

Question 4

Which equation correctly represents the magnitude of the electric force between two point charges $$Q_1$$ and $$Q_2$$ separated by a distance $$r$$?

Accepted Answer

$$F = \frac{Q_1$ Q_2$}{4 \pi \$$epsilon_0$$ r^2$}$$

Question 5

If three point charges are placed at the corners of a square, what is the correct method to find the net electric field at the fourth corner?

Accepted Answer

Add the electric fields from each charge as vectors.

Question 6

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

Accepted Answer

The number of field lines leaving a positive charge is proportional to the magnitude of the charge.

Question 7

What is the net electric field inside a conductor in electrostatic equilibrium?

Accepted Answer

It is zero.

Question 8

A charged particle of mass $$m$$ and charge $$q is $$placed in a uniform electric field $$E. $$What is the acceleration of the particle?

Accepted Answer

$$a = \frac{qE}{m}$$

Question 9

Suppose an electron enters a uniform electric field region parallel with the field lines. If its initial velocity is $$v_0 = 3.5$$ 	imes $$10^6 m/s $$and it stops after $$d = 4 cm$$, what is the magnitude of the electric field? (Electron charge $$e = 1.6 	imes 10$$^{-19}$$ C, mass m = 9.1$$ 	imes $$10^{-31} kg)$$

Accepted Answer

$$E = 3.5 	imes 10^3$ N/C

Question 10

Which of the following best explains why the net electric field at the center of a uniformly charged spherical conductor is zero?

Accepted Answer

The electric field from each part of the surface cancels at the center.

Question 11

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

Accepted Answer

It is always perpendicular to the surface.

Question 12

A Van de Graaff generator is an example of which phenomenon?

Accepted Answer

Static electricity

Question 13

Which of the following best describes the direction of the electric field at a point in space?

Accepted Answer

It is tangent to the electric field line at that point.

Question 14

If a neutral metal doorknob is touched by a positively charged rod, what happens?

Accepted Answer

Electrons move from the doorknob to the rod.

Question 15

Which of the following is a correct statement about the superposition principle for electric forces?

Accepted Answer

The net force is the vector sum of the individual forces.

Question 16

A solid object is negatively charged. Which of the following is true?

Accepted Answer

It has a surplus of electrons.

Question 17

Which of the following best describes the electric field created by a uniformly charged infinite line at a distance $$r$$ from the line?

Accepted Answer

$$E = \frac{\lambda}{2 \pi \$$epsilon_0$$ r}$$

Question 18

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

Accepted Answer

They are always straight lines.

Question 19

What is the trajectory of a charged particle in a uniform electric field if its initial velocity is perpendicular to the field lines?

Accepted Answer

A parabolic path.

Electric Charge and Electric Field: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards