Physics 011

PQ#16

Chapter 16: Electric Charge and Electric Field
Practice Questions

 1

Electrons carry a

positive charge.

negative charge.

neutral charge.

variable charge.

 2

The units of Coulomb's constants are

Nm2/C2

Nm

Nm/C2

C2

 3

The units of permittivity are

unitless

1/4*pi

Nm2

C2/Nm2

 4

The unit of a charge is the

N(ewton)

m(eter)

J(oule)

C(oulomb)

 5

Which of the following are the units of electric field?

N

N*C

N/C

N/m2

 6

Two charges Q1 and Q2 are separated by a distance D. If the distance is doubled, the force is

increased by a factor of 2.

decreased by a factor of 2.

remains the same.

increased by a factor of 4.

decreased by a factor of 4.

 7

Two charges Q1 and Q2 are separated by a distance D. If Q1 is doubled, the force is

increased by a factor of 2.

decreased by a factor of 2.

remains the same.

increased by a factor of 4.

decreased by a factor of 4.

 8

Two charges Q1 and Q2 are separated by a distance D. If Q1 and Q2 are doubled, the force is

increased by a factor of 2.

decreased by a factor of 2.

remains the same.

increased by a factor of 4.

decreased by a factor of 4.

 9

Two charges Q1 and Q2 are separated by a distance D. If both Q1 and D are doubled, the force is

increased by a factor of 2.

decreased by a factor of 2.

remains the same.

increased by a factor of 4.

decreased by a factor of 4.

 10

Two charges Q1 and Q2 are separated by a distance D. If Q1, Q2 and D are all doubled, the force is

increased by a factor of 2.

decreased by a factor of 2.

remains the same.

increased by a factor of 4.

decreased by a factor of 4.

 11 In the above figure, if Q1 is negative and has magnitude less than Q2 which is positive, where could a positive charge be placed and possibly have a zero net force on it?

A

B

C

D

E

 12 In the above figure, if Q1 and Q2 are positive, where could a negative charge be placed and have a vertically upward net force on it?

A

B

C

D

E

 13 In the above figure, if Q1 and Q2 are positive, where would the electric field be vertically upward ?

A

B

C

D

E

 14 In the above figure, if Q1 and Q2 are positive and the same size, where would the electric field be zero ?

A

B

C

D

E

Not shown.

 15 In the above figure, if Q1 is negative and Q2 is positive and are both the same magnitude, where would the electric field be zero ?

A

B

C

D

E

Nowhere shown.

 16 In the above figure, if Q1 is negative and Q2 is positive and the distance from Q2 to point C is 1/4 the distance between the charges, how many times greater than Q2 in magnitude must Q1 be for the Electric field to be zero at C?

4

10

16

20

25

 17 In the above figure if the vertical distance from point E to B is the same as the horizontal distance from E to either charge and the electric field at B from either charge has magnitude 1.0x106, what is the magnitude of the net electric field?

zero

7.1x105

1.0x106

1.4x106

2.0x106

 18 In the above figure the vertical distance from point E to B is the same as the horizontal distance from E to either charge and the electric field at B from either charge has magnitude 1.0x106. If Q1 is negative and Q2 is positive what is the direction of the net electric field at B?

Vertical and up.

Horizontal and to the right.

Vertical and down.

Horizontal and to the left.

 19 In the above figure the vertical distance from point E to B is the same as the horizontal distance from E to either charge and the electric field at B from either charge has magnitude 1.0x106. If both Q1 and Q2 are positive what is the direction of the net electric field at B?

Vertical and up.

Horizontal and to the right.

Vertical and down.

Horizontal and to the left.

 20 The figure above shows a metal shell surrounding a positive charge. What is the charge on the metal surface at b?

negative

zero

positive

 21 The figure above shows a metal shell surrounding a positive charge. Which of the following statements is true?

The electric field at e is less than that at a and c.

The electric field at c is greater than that at a and e.

The electric field at c is less than that at a and e.

The electric field at e is greater than that at a.

 22

In question 20 what would be the charge on the exterior surface (d)?

negative

zero

positive

 23

Four people tell you they have a negative charge of a certain value. Which one is not telling the truth?

Mine is 1.90x10-18 Coulomb.

Mine is 1.6x10-18 Coulomb.

Mine is 1.92x10-18 Coulomb.

Mine is 2.4x10-16 Coulomb.

 24

What must be the charge on each of two 100 kg spherical masses in order for the electrical force to equal the gravitational force?

8.6x10-19 C

8.6 nanoC

7.4x10-17 C

100 C

 25

How many electrons would it take to make up a charge of minus one millionth of a Coulomb?

100000

10000000

8x1042

6.25x1012