AP Physics C Sources of Magnetic Field Multiple Choice Slide 2 / - - PDF document

AP Physics C Sources

• f Magnetic Field

Multiple Choice

Slide 1 / 22

1 Two long parallel wires are separated by distance R carrying two currents, I1 and I2 respectively. To increase the force exerted on each wire by two times as much, you could:

• I. Double the current and double the separation
• II. Double one current only and keep the

separation same

• III. Keep the currents the same and halve the

separation

A I only B

I & II

C

I & III

D

II & III

E

I, II & III

Slide 2 / 22

2 Two long, parallel wires, fixed in space, carry current I1 and I2. The force of attraction has magnitude F. Waht currents will give an attractive force of magnitude 4F?

A

2 I1 and 1/2 I2

B

I1 and 1/4 I2

C

1/2 I1 and 1/2 I2

D

2 I1 and 2 I2

E

4 I1 and 4 I2

Slide 3 / 22

3 A solid cylindrical conductor of adius R carries a current I uniformly distributed throughout its

• interior. Which of the following graphs best

represents the magnetic field intensity as a function of r, the radial distance from the axis of the cylinder?

A B C D E

Slide 4 / 22

4 The cross section below shows a long solenoid of length l and radius r consisting of N closely wound turns of wire. When the current in the wire is I, the magnetic field within this solenoid has magnitude

• Bo. A solenoid with the same number of turns N,

length l, and current I, but with radius 2r, would have a magnetic field of magnitude most nearly equal to

A

Bo/4

B

Bo/2

C

Bo

D

2Bo

E

4Bo

Slide 5 / 22

5 Two very long parallel wires carry equal currents in the same direction into the page, as shown

• below. At point T, which is 10 cm from each wire,

the magnetic field is

A zero B

directed into the page

C

directed out of the page

D

directed to the left

E

directed to the right

Slide 6 / 22

6 Two long wires carrying currents in the same direction are placed next to each other. Which of the following is true?

A The wires will remain in place B

The wires will rotate clockwise

C

The wires will rotate counter-clockwise

D

The wires will attract each other

E

The wires will repel each other

Slide 7 / 22

7 A current I, uniformly distributed over the cross section of a long cylindrical conductor of radius a, is directed as shown below. Which of the following graphs best represents the intensity of the magnetic field B as a function of the distance r from the axis of the cylinder?

A B C D E

Slide 8 / 22

8 Which of the following equations implies that it is impossible to isolate a magnetic pole?

A B C D E

None of the above

Slide 9 / 22

9 Questions 9-10 Two long, parallel wires are shown below. Initially, the wires are a distance d apart and each has a current I directed into the page. The force per unit length on each wire has magnitude Fo. The direction of the force on the right-hand wire due to the current in the left-hand wire is

A to the right B

to the left

C

upward in the plane of the page

D

downward in the plane of the page

E

into the page

Slide 10 / 22

10 Questions 9-10 Two long, parallel wires are shown below. Initially, the wires are a distance d apart and each has a current I directed into the page. The force per unit length on each wire has magnitude Fo. The wires are moved apart to a separation of 2d and the current in each wire is increased to 2I. The new force per unit length on each wire is

A Fo/4 B

Fo/2

C

Fo

D

2Fo

E

4Fo

Slide 11 / 22

11 Two long parallel wires are a distance 2a apart, as shown below. Point P is in the pane of the wires and a distance a from wire X. When there is a current I in wire X and no current in wire Y, the magnitude of the magnetic field at P is Bo. When there are equal currents I in the same direction in both wires, the magnitude of the magnetic field at P is

A

2Bo/3

B

Bo

C

10Bo/9

D

4Bo/3

E

2Bo

Slide 12 / 22

12 A rigid, rectangular wire loop ABCD carrying current I1 lies in the plane of the page above a very long wire carrying current I2 as shown below. The net force on the loop is

A toward the wire B

away from the wire

C

toward the left

D

toward the right

E

zero

Slide 13 / 22

13 A cross section of a long solenoid that carries current I is shown below. All of the following statements about the magnetic field B inside the solenoid are correct EXCEPT:

A B is directed to the left. B

An approximate value for the magnitude of B may be determined by using Ampere's law.

C

The magnitude of B is proportional to th current I.

D

The magnitude f B is proportional to the number of turns of wire per unit length.

E

The magnitude of B is proportional to the distance from the axis of the solenoid.

Slide 14 / 22

14 In which of the following cases does a nonzero magnetic field exist that can be conveniently determined by using Ampere's law?

A Outside a point charge that is at rest B Inside a stationary cylinder carrying a

uniformly distributed charge

C Inside a very long current-carrying

solenoid

D At the center of a current-carrying loop of wire E Outside a square current-carrying loop of wire

Slide 15 / 22

15 Questions 15-16 The figure below depicts a wire that has been bent into a semi-circle of radius R in one section. A current I passes through the wire. What direction does the magnetic field point at the center of the semi-circle.

A To the right B

To the left

C

Out of the page

D

Into the page

E

Downward

Slide 16 / 22

16 Questions 15-16 The figure below depicts a wire that has been bent into a semi-circle of radius R in one section. A current I passes through the wire. What is the magnitude of the magnetic field at the center of the semi-circle?

A B C D E

Slide 17 / 22

17 Questions 17-19 A magnetic field is created by a current I that runs through the circular loop as shown below. Which of the following represents the magnetic field strength at the center of the loop?

A zero B C D E

Slide 18 / 22

18 Questions 17-19 A magnetic field is created by a current I that runs through the circular loop as shown below. Which of the following represents the magnetic field strength at a distance x away from the loop?

A zero B C D E

Slide 19 / 22

19 Questions 17-19 A magnetic field is created by a current I that runs through the circular loop as shown below. Where is the strength of the magnetic field the largest?

A At a distance x away from the loop B

At a distance a away from the loop

C

At a distance 2a away from the loop

D

At a distance 2x away from the loop

E

At the origin

Slide 20 / 22

20 A cross section of a long, cylindrical conductor of radius R2 has a current uniformly distributed as shown below. Which of the following represents the magnetic field at a distance R1<R<R2?

A zero B C D E

Slide 21 / 22

Slide 22 / 22