1. Physics of Everyday Phenomena
W. Thomas Griffith
Juliet W. Brosing
Chapter 14
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. Question 14.1 With magnets A) like poles repel one another
B) like poles attract one another
C) unlike poles repel one another

3. Question 14.2 The force between two unlike magnetic poles
A) increases linearly with the separation distance between them
B) increases as the square of the separation distance between them
C) decreases linearly as the separation distance between them
D) decreases as the square of the separation distance between them

4. Question 14.3
A magnet on a frictionless mount would have its magnetic north pole point toward the
Earth’s geographic
A) south pole
B) north pole

5. Question 14.4 The magnetic field lines of a bar magnet
A) emerge from the north pole and go back into the north pole
B) emerge from the north pole and go into the south pole
C) emerge from the south pole and go back into the south pole
D) emerge from the south pole and go into the north pole

6. Answer to Q14.4
B. The magnetic field lines of a bar magnet emerge from the north pole and go into the south pole

7. Question 14.5
The magnetic field lines produced by a current in a straight wire
A) are directed outward in a direction perpendicular to the wire
B) are directed in concentric circles around the wire
C) begin on one side of the wire and end on the other side of the wire

8. Answer to Q14.5
B. The magnetic field lines produced by a current in a straight wire are directed in concentric circles around the wire

9. Question 14.6
Two wires, each carrying current I, are antiparallel to each other. The two wires
A) repel each other.
B) attract each other.
C) are not affected by each other.

10. Answer to 14.6
A. Two wires, each carrying current I, are antiparallel to each other. The two wires repel each other.

11. Question 14.7
A cross section of the magnetic field for a current-carrying wire is shown. The direction of the current is
A) to the left.
B) to the right.

12. Answer to 14.7
The direction of the current is to left. The fingers are curling out of the paper below the wire, as shown in the B field diagram.

13. Question 14.8
A current loop is placed in a magnetic field as indicated. Will the loop tend to rotate (viewed from above) clockwise, counter-clockwise, or not at all about a vertical axis?
A) clockwise
B) counter-clockwise
C) not at all

14. Question 14.9
A current loop is placed in a magnetic field which is coming out of the board, as indicated. Will the loop tend to rotate
clockwise, counter-clockwise, or not at all about a vertical axis?
A) clockwise
B) counter-clockwise
C) not at all

15. Question 14.10
A coil of wire rotates in the space between the poles of an electromagnet that produces a
uniform magnetic field. If the rotation rate is increased, the maximum output voltage
A) increases.
B) stays the same.
C) decreases.

16. Question 14.11
According to Faraday’s Law of Electromagnetic Induction, the induced voltage is equal to
A) the rate of change of the magnetic flux
B) the rate of change of the magnetic field strength
C) the rate of change of the magnetic force
D) the rate of change of the loop area

17. Question 14.12
According to Lenz’s Law the direction of the induced current produced by a changing
magnetic flux is such as to produce a magnetic field that
A) reinforces the change in the original magnetic flux.
B) opposes the change in the original magnetic flux.

18. Question 14.13
A bar magnet passes through a circular loop of wire as shown below. At the instant that
the middle of the magnet passes through the loop, the induced current ( as seen from the coil # 2) is
A) ccw and increasing.
B) cw and decreasing.
C) cw and increasing.
D) zero.

19. Question 14.14
A quarter is dropped down a hollow metal pipe and falls out the bottom T seconds later. A
magnet is then dropped down the same pipe and falls out the bottom t seconds later. Which of the following is true?
A) t = T
B) t > T
C) t < T

20. Question 14.15
High voltages are desirable for long distance transmission of electric power because
A) the higher the voltage the higher the current, which reduces the power lost
B) the higher the voltage, the lower the current, which reduces the power lost
C) the higher the voltage the less concern there is for safety

21. Answer Key to Chapter 14 A D B C A B