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Assessment

Chapter Test A
Teacher Notes and Answers
Electromagnetic Induction
CHAPTER TEST A (GENERAL)
1. c 14. b
2. d Given
3. b
V1 = 115 V
4. d
V2 = 2.3 V
5. a Solution

V 115 V
6. d N1 : N 2 = 1 = = 50 : 1
7. b
V2 2.3 V
8. c 15. c
9. c 16. b
10. d 17. b
11. c 18. b
Given 19. Move the circuit loop into or out of the

Vmax = 220 V magnetic field. Rotate the circuit loop in the
Solution magnetic field so that the angle between the

Vrms = 0.707
Vmax = plane of the circuit loop and magnetic field
(0.707)(220 V) = 160 V changes. Vary the intensity of the magnetic
12. a field by rotating the magnet.
Given
20. to turn wire loops (or a coil of wire) in a
I rms = 3.6 A
magnetic field
Solution 21. the rms current multiplied by the resistance
Rearrange the equation, I rms =
(or I rms • R )
0.707 I max , to solve for I max . 22. The energy of an electromagnetic wave is
I rms (3.6 A) stored in the electromagnetic fields, which
I max = = = 5.1 A
0.707 (0.707) exert an electromagnetic force on charged
13. d particles. This energy transported by an
Given electromagnetic wave is called

V1 = 120 V electromagnetic radiation.
N 1 = 95 turns
N 2 = 2850 turns
Solution

V2 N 2  2850 turns 

V2 = = (120 V)  
N1  95 turns 
= 3600 V

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Holt Physics 1 Chapter Tests
Name:______________________________Class:__________________ Date:__________________
23. 149 V 24. 297 V
Given Given
N = 275 turns
Vmax = 4.20  102 V
A = 0.750 m2 Solution

Vrms = 0.707
Vmax =

B = +0.900 T
(0.707)(4.2  102 V) = 297 V

t = 1.25 s 25. 1.6  104 V
 = 0.00° Given
Solution
V1 = 120 V
Substitute values into Faraday’s law of
N 1 = 38 turns
magnetic induction.
N 2 = 5163 turns
N
 M
ABcos 
emf = = N = Solution

t
t N  5163 turns 

B
V2 =
V1 2 = (120 V) 
 NAcos  N1  38 turns 

t
= 1.6  10 4 V
=  (275 turns)(0.750 m2 )
(0.900 T)
(cos 0.00°) = 149 V
(1.25 s)

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Holt Physics 2 Chapter Tests
Name:______________________________Class:__________________ Date:__________________

Assessment

Electromagnetic Induction
Chapter Test A
MULTIPLE CHOICE
In the space provided, write the letter of the term or phrase that best completes
each statement or best answers each question.

_____ 1. A current can be induced in a closed circuit without the use of a battery
or an electrical power supply by moving the circuit through a
a. high temperature field. c. magnetic field.
b. gravitational field. d. nuclear field.

_____ 2. A loop of wire is held in a vertical position at the equator with the face
of the loop facing in the east-west direction. What change will induce
the greatest current in the loop?
a. raising the loop to a higher elevation
b. moving the loop north
c. rotating the loop so its face is vertical
d. rotating the loop so its face is north-south

_____ 3. Electricity may be generated by rotating a loop of wire between the

poles of a magnet. The induced current is greatest when
a. the plane of the loop is parallel to the magnetic field.
b. the plane of the loop is perpendicular to the magnetic field.
c. the magnetic flux through the loop is a minimum.
d. the plane of the loop makes an angle of 45° with the magnetic field.

_____ 4. According to Lenz’s law, the magnetic field of an induced current in a

conductor will
a. enhance the applied field.
b. heat the conductor.
c. increase the potential difference.
d. oppose a change in the applied magnetic field.

_____ 5. According to Lenz’s law, if the applied magnetic field changes,

a. the induced field attempts to keep the total field strength constant.
b. the induced field attempts to increase the total field strength.
c. the induced field attempts to decrease the total field strength.
d. the induced field attempts to oscillate about an equilibrium value.

_____ 6. Which of the following options can be used to generate electricity?

a. Move the circuit loop into and out of a magnetic field.
b. Change the magnetic field strength around the circuit loop.
c. Change the orientation of the circuit loop with respect to the magnetic
field.
d. all of the above

Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Physics 3 Chapter Tests
Name:______________________________Class:__________________ Date:__________________

Chapter Test A continued

_____ 7. Which conversion process is the basic function of the electric motor?
a. mechanical energy to electrical energy
b. electrical energy to mechanical energy
c. low voltage to high voltage, or vice versa
d. alternating current to direct current
_____ 8. In a two-coil system, the mutual inductance depends on
a. only the geometrical properties of the coils.
b. only the orientation of the coils to each other.
c. both the geometrical properties of the coils and their orientation to
each other.
d. neither the geometrical properties of the coils nor their orientation to
each other.
_____ 9. In a primary-secondary coil combination, which of the following
conditions is met in the primary coil when the current in the secondary
coil is at its maximum?
a. The current is maximum in a positive direction.
b. The current is maximum in a negative direction.
c. The rate of current change is maximum.
d. The voltage is maximum in a positive direction.
_____ 10. What is rms (root-mean-square) current?
a. the value of alternating current that gives the same heating effect
that the corresponding value of direct current does
b. an important measure of the current in an ac circuit
c. the amount of direct current that would dissipate the same energy in
a resistor as is dissipated by the instantaneous alternating current
over a complete cycle
d. all of the above
_____ 11. A generator’s maximum output is 220 V. Calculate the rms potential
difference.
a. 110 V c. 160 V
b. 150 V d. 310 V
_____ 12. The rms current in an ac current is 3.6 A. Find the maximum current.
a. 5.1 A c. 2.8 A
b. 4.7 A d. 1.8 A
_____ 13. A step-up transformer used on a 120 V line has 95 turns on the primary
and 2850 turns on the secondary. What is the potential difference
across the secondary?
a. 30 V c. 2400 V
b. 1800 V d. 3600 V

Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Physics 4 Chapter Tests
Name:______________________________Class:__________________ Date:__________________

Chapter Test A continued

_____ 14. A potential difference of 115 V across the primary of a step-down

transformer provides a potential difference of 2.3 V across the
secondary. What is the ratio of the number of turns of wire on the
primary to the number of turns on the secondary?
a. 1:50 c. 25:1
b. 50:1 d. 1:25
_____ 15. Electromagnetic waves are _________________ electric and magnetic
fields.
a. transverse c. oscillating
b. constant d. parallel
_____ 16. All of the following statements about the electromagnetic force are true
except which one?
a. It is one of the four fundamental forces in the universe.
b. It exerts a force on either charged or uncharged particles.
c. It obeys the inverse-square law.
d. It is produced by—and produces—electric and magnetic fields.
_____ 17. Where is energy stored in electromagnetic waves?
a. in the wave’s moving atoms
b. in the oscillating electric and magnetic fields
c. in the electromagnetic force
d. in the wave’s directional vector
_____ 18. What do radio waves, microwaves, X rays, and gamma rays all have in
common?
a. They are produced in the same way.
b. They are electromagnetic waves.
c. They are detected in the same way.
d. They store the same amount of energy.

SHORT ANSWER
19. List three ways to induce a current in a circuit loop, using only a magnet.
_________________________________________________________________

_________________________________________________________________

_________________________________________________________________
20. What is a turbine’s rotational motion used for in commercial power plants?
_________________________________________________________________

_________________________________________________________________

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Holt Physics 5 Chapter Tests
Name:______________________________Class:__________________ Date:__________________

Chapter Test A continued

21. The rms emf across a resistor is equal to what?

_________________________________________________________________

_________________________________________________________________
22. Explain how the terms energy, electromagnetic force, electromagnetic wave,
and electromagnetic radiation are related to one another.
_________________________________________________________________

_________________________________________________________________

_________________________________________________________________

_________________________________________________________________

PROBLEM
23. A coil with 275 turns and a cross-sectional area of 0.750 m2 experiences a
magnetic field whose strength increases by +0.900 T in 1.25 s. The plane of
the coil moves perpendicularly to the plane of the magnetic field. What is the
induced emf in the coil?

24. An ac generator has a maximum output emf of 4.20
102 V. What is the rms
potential difference?

25. A step-up transformer used on a 120 V line has 38 turns on the primary and
5163 turns on the secondary. What is the potential difference across the
secondary?

Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Physics 6 Chapter Tests