Questions: Introduction to Electric Fields

Question 1

In which direction do electric field lines point around a single positive charge?

• A. Toward the charge
• B. Away from the charge
• C. In circles around the charge
• D. They do not have a direction

Answer: (B)

By convention, electric field lines point in the direction a positive test charge would be pushed. Since like charges repel, a positive test charge would be pushed away from a positive source charge.

Question 2

Electric field lines are closer together where the field is stronger.

• T. True
• F. False

Answer: True

The density of field lines represents field strength. Closely spaced lines mean strong field; widely spaced lines mean weak field.

Question 3

What does an electric field tell you about a point in space?

Model answer: It tells you the direction and strength of the electric force that would act on a positive test charge placed at that point.

The electric field at a point is defined as the force per unit positive charge: E = F/q. It describes what force a charge would experience if placed there, even if no charge is actually present.