Chapter 15: Electric Forces and Fields

Question 1

A positively charged particle moves from near two protons to near two electrons. As it does, it’s electric potential energy:

a. Decreases and moves towards point 2 with an increasing speed
b. Stays the same and remain at rest
c. Decreases and moves towards point 2 with an decreasing speed
d. Increases and moves towards point 2 with a decreasing speed

Answer 1

Decreases and moves towards point 2 with an increasing speed

Question 2

A suspended object A is attracted to a neutral wall. It’s also attracted to a positively-charged object B. Which of the following is true about object A?
Select one:
a. It has a negative charge.
b. It has a positive charge.
c. It may be either charged or uncharged.
d. It is uncharged.

Answer 2

It has a negative charge.

Question 3

A test charge of –q at point P is used to measure an electric field. The field is found to have a magnitude of 2 N/C. When the charge –q is removed, the electric field at point P.
Select one:
a. changes in a way that cannot be determined from the information given.
b. will change in magnitude.
c. will reverse in direction.
d. will have magnitude 2 N/C.

Answer 3

will have magnitude 2 N/C.

Question 4

A test charge of +3 μC is at a point P where the electric field due to other charges is directed to the right and has a magnitude of 4 X 106 N/C. If the test charge is replaced with a –3 μC charge, the electric field at P
Select one:
a. has the same magnitude as before, but changes direction.
b. remains the same.
c. decreases in magnitude and changes direction.
d. increases in magnitude and changes direction.

Answer 4

remains the same.

Question 5

If an electron is released from rest in a uniform electric field, the electric potential energy of the charge-field system
Select one:
a. decreases
b. It may be either increased or decreased.
c. remains the same
d. increases

Answer 5

decreases

Question 6

Point A is close to an electron. Point B is further from the electron. Points A and B and the electron are along a straight line. Which of the following statements are true?
Select one:
a. The field is stronger at point A than B and is directed from B to A.
b. The field is stronger at point B than A and is directed from B to A.
c. The field is weaker at point B than A and is directed from A to B.
d. The field is weaker at point A than B and is directed from A to B.

Answer 6

The field is stronger at point A than B and is directed from B to A.

Question 7

You are given four objects, A, B, C, and D. You discover that A and B repel each other, and that C and D repel each other. If B and C attract each other, which of the following are possible charges for A, B, C, and D in that order?
Select one:
a. A +, B +, C –, D – 
b. A –, B +, C +, D –
c. A +, B +, C –, D +
d. A –, B –, C –, D +

Answer 7

A +, B +, C –, D –