Charges and electric potential mastering physics

11/30/2018 HW3

https://session.masteringphysics.com/myct/assignmentPrintView?displayMode=studentView&assignmentID=6826674 1/12

HW3 Due: 11:59pm on Friday, October 5, 2018

You will receive no credit for items you complete after the assignment is due. Grading Policy

Exercise 23.10

Four electrons are located at the corners of a square 10.0 on a side, with an alpha particle at its midpoint.

Part A

How much work is done by the Coulomb force when the alpha particle moves to the midpoint of one of the sides of the square?

ANSWER:

Exercise 23.2

A point charge is held stationary at the origin. A second charge is placed at point , and the electric potential energy of the pair of charges is . When the second charge is moved to point , the electric force on the charge does

of work.

Part A

What is the electric potential energy of the pair of charges when the second charge is at point ?

Express your answer using two significant figures.

ANSWER:

Exercise 23.16

Two stationary point charges + 3.00 and + 2.00 are separated by a distance of 50.0 . An electron is released from rest at a point midway between the two charges and moves along the line connecting the two charges.

Part A

What is the speed of the electron when it is 10.0 from the + 3.00- charge?

ANSWER:

Exercise 23.39

nm

= W J

q1 q2 a

+5.4 × J10−8 b −1.9 × J10−8

b

J

nC nC cm

cm nC

= v m/s

11/30/2018 HW3

https://session.masteringphysics.com/myct/assignmentPrintView?displayMode=studentView&assignmentID=6826674 2/12

The electric field at the surface of a charged, solid, copper sphere with radius 0.250 is 3500 , directed toward the center of the sphere. .

Part A

What is the potential at the center of the sphere, if we take the potential to be zero infinitely far from the sphere?

ANSWER:

Conceptual Question 23.01

Part A

If the electric field is zero everywhere inside a region of space, the potential must also be zero in that region.

ANSWER:

Conceptual Question 23.03

Part A

If the electrical potential in a region is constant, the electric field must be zero everywhere in that region.

ANSWER:

Conceptual Question 23.06

Part A

Suppose a region of space has a uniform electric field, directed towards the right, as shown in the figure. Which statement about the electric potential is true?

m N/C

= V V

True

False

True

False

11/30/2018 HW3

https://session.masteringphysics.com/myct/assignmentPrintView?displayMode=studentView&assignmentID=6826674 3/12

ANSWER:

Conceptual Question 23.08

Part A

Suppose you have two point charges of opposite sign. As you move them farther and farther apart, the potential energy of this system relative to infinity

ANSWER:

Conceptual Question 23.13

Part A

A nonconducting sphere contains positive charge distributed uniformly throughout its volume. Which statements about the potential due to this sphere are true? All potentials are measured relative to infinity. (There may be more than one correct choice.)

Choose all that apply.

ANSWER:

The potential at points and are equal, and the potential at point is higher than the potential at point .A B C A

The potential at all three locations ( , , ) is the same because the field is uniform.A B C

The potential at point is the highest, the potential at point is the second highest, and the potential at point is the lowest.