Question

Which of the following statements about electric field lines are true? (choose all that are true)

a) They are only defined for positive charges.

b) They are always tangent to electric field vectors.

c) They are always perpendicular to charged surfaces.

d) They are a simple way to visualize the electric field vectors. e) None of the above.

If a negative charge is placed in an electric field, what direction will it be accelerated?

a) In the direction of the field.

b) In the opposite direction of the field.

c) Perpendicular to the direction of the field.

d) It will not be accelerated.

e) None of the above.

What is an electric field? (choose all that are true)

a) A vector field created by a charged particle.

b) The field created when one charged particle is brought close to another charged particle.

c) A scalar field created by a charged particle.

d) A vector field created only by positive charges.

e) None of the above.

When the electric field strength is large, electric field lines are:

a) close together.

b) perpendicular to each other.

c) electric field lines are not related to the field strength.

d) far apart.

e) None of the above.

The electric field surrounding two point charges

a) is the vector sum of the electric field that would be caused by each charge separately.

b) zero at all points along the line connecting the two charges.

c) cannot be determined.

d) cannot be zero anywhere.

e) None of the above.

The electric field due to two point charges is found by:

a) finding the stronger field. The net field will just be equal to the strongest field.

b) determining the electric field due to each charge and adding them together as vectors.

c) adding the magnitude of the two fields together.

d) adding the direction of the two fields together.

e) None of the above.

What does it mean if a conductor is in “electrostatic equilibrium”?

a) The conductor is at rest.

b) The charges in the conductor are not moving.

c) The charges in the conductor are distributed uniformly throughout the conductor.

d) The charges in the conductor are moving in response to an electric field.

e) None of the above.

For a positive point charge, the electric field vectors point in what direction?

a) Point charges cannot create an electric field.

b) Along a circle around it.

c) Toward it.

d) Away from it.

e) None of the above.

An unknown charge sits at the origin. The electric field is measured at a point on the x-axis at x = −3.0cm and is found to be 8.0NC−1, pointing in the +x direction. Which of the following statements can be made? (Choose all that apply)

a) The charge is negative.

b) The electric field strength at a point on the x-axis at x = 6 cm will be 2.0 N C−1.

c) The electric field strength at a point on the y-axis at y = 6 cm will be 2.0 N C−1.

d) The charge is positive.

e) None of the above.

Answer 1

1) Which of the following statements about electric field lines are true? (choose all that are true)

b) They are always tangent to electric field vectors.

2) If a negative charge is placed in an electric field, what direction will it be accelerated?

b) In the opposite direction of the field.

because, a = q*E/m, a is acceleration of charge, m is mass of charge, q is the charge of charge.

3) What is an electric field? (choose all that are true)

a) A vector field created by a charged particle.

4) When the electric field strength is large, electric field lines are:

a) close together.

5) The electric field surrounding two point charges

a) is the vector sum of the electric field that would be caused by each charge separately.

6) The electric field due to two point charges is found by:

b) determining the electric field due to each charge and adding them together as vectors.

7) What does it mean if a conductor is in “electrostatic equilibrium”?

b) The charges in the conductor are not moving.

8) For a positive point charge, the electric field vectors point in what direction?

d) Away from it.

9) An unknown charge sits at the origin. The electric field is measured at a point on the x-axis at x = −3.0cm and is found to be 8.0NC−1, pointing in the +x direction. Which of the following statements can be made? (Choose all that apply)

a) The charge is negative.

b) The electric field strength at a point on the x-axis at x = 6 cm will be 2.0 N C−1.

c) The electric field strength at a point on the y-axis at y = 6 cm will be 2.0 N C−1.

E = k*q/r²

for r = 3.0 cm given E = 8 N/C

for r = 6.0 cm E = 8/4 = 2 N/C (for option b and c)