Question 1

The image showing two positive charges with electric field lines radiating outward best illustrates which property of electric fields?

Accepted Answer

Electric field lines start on positive charges and never cross each other.

Question 2

Given the formula $$\vec{E} = \frac{1}{4\pi\$$epsilon_0$$} \frac{q}{r^2$} \hat{r}$$, what happens to the electric field strength if the distance from the point charge is doubled?

Accepted Answer

It becomes one fourth as strong.

Question 3

Which of the following best describes the electric field between the plates of a parallel-plate capacitor, as shown in the diagram with straight, evenly spaced field lines?

Accepted Answer

The electric field is uniform in magnitude and direction between the plates.

Question 4

A proton enters a region between two parallel plates with a uniform electric field directed downward. Which path will the proton follow?

Accepted Answer

It will curve upward, following a parabolic trajectory.

Question 5

Which experiment, shown in the images, was used to measure the charge-to-mass ratio of the electron?

Accepted Answer

Cathode-ray tube experiment

Question 6

In the Millikan oil-drop experiment, what was the primary purpose of the uniform electric field between the plates?

Accepted Answer

To balance the gravitational force on the charged oil drops

Question 7

A water molecule is shown with a partial negative charge on the oxygen and partial positive charges on the hydrogens. What property does this illustrate?

Accepted Answer

Water is an electric dipole.

Question 8

If a charged particle moves through a region with a uniform electric field, what is the nature of its acceleration?

Accepted Answer

It experiences a constant acceleration.

Question 9

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

Accepted Answer

Electric field lines are tangent to the electric field vector at every point.

Question 10

A dipole is placed in a uniform electric field. What is the net force and torque on the dipole?

Accepted Answer

Zero net force and nonzero torque.

Question 11

The electric field outside a uniformly charged sphere is identical to the field produced by:

Accepted Answer

A point charge located at the center of the sphere.

Question 12

Which of the following best describes the electric field of an infinite plane of charge?

Accepted Answer

It is constant everywhere.

Question 13

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

Accepted Answer

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

Question 14

If two protons are placed at different distances from an infinite plane of positive charge, which one experiences a greater acceleration?

Accepted Answer

Both experience the same acceleration.

Question 15

Which of the following is true about the electric field inside an ideal parallel-plate capacitor?

Accepted Answer

It is uniform and constant everywhere between the plates.

Question 16

A dipole is placed near a positive point charge in a nonuniform electric field. What is the net force on the dipole?

Accepted Answer

Toward the point charge.

Question 17

The surface charge density $$\eta$$ for a flat circular ring of charge $$Q$$, radius $$R$$, and width $$w ($$with $$w \ll R) is$$:

Accepted Answer

$$\frac{Q}{2\pi R w}$$

Question 18

Which of the following best describes the motion of an electron in a uniform electric field between two parallel plates?

Accepted Answer

It follows a parabolic trajectory.

Question 19

If the total charge $$Q is $$distributed uniformly along a rod of length $$L$$, what is the linear charge density $$\lambda$$?

Accepted Answer

$$\lambda = \frac{Q}{L}$$

Question 20

Which of the following is a real-world application of a uniform electric field?

Accepted Answer

The field inside a parallel-plate capacitor.

Chapter 23: The Electric Field – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards