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Date:
Name:
Class:
Assessment
Chapter 16 Pre-Test
Chapter 16
BLM 16-7
Goal
To assess your understanding of the key concepts studied in Chapter 16.
Procedure
Answer the following questions in the space provided.
1.
A positive charge is travelling away from you into the page between two magnets,
as shown in the diagram. In which direction will the charge be deflected? ____
(a) left
(b) right
(c) up
(d) down
2.
The force on a current-carrying wire in a magnetic field is both ___ the direction
of the magnetic field and the direction of the current.
(a) parallel to
(b) opposite to
(c) at right angles to
(d) independent of
3.
Which one of the following actions produces attractive forces? ____
(a) bringing the north poles of two magnets together
(b)
placing a current-carrying wire east-west above a compass
(c) placing two wires, with currents flowing in the same direction, parallel to one
another
(d) pushing a wire between the ends of a horseshoe magnet
4.
Which description is accurate for a magnetic force experienced by a charged
particle moving through a magnetic field? _____
(a) The force is always greater than zero.
(b) The force is constant, regardless of the direction of the field.
(c) The force is at maximum when the particle’s velocity is parallel to the field.
(d) The force is at maximum when the particle’s velocity is perpendicular to the
field.
Copyright © 2003 McGraw-Hill Ryerson Limited.
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5.
Class:
When a positive charge enters a motor, it passes through a coil of wire. What type
of field does the flow of charge create? _____
(a) electric field
(b) force field
(c) gravitational field
(d) magnetic field
6.
Which of the following is a characteristic of the magnetic field about a bar
magnet? _____
(a) The field lines attract each other.
(b) The field lines cross one another near the poles.
(c) The field lines form closed curves.
(d) The field lines are more numerous near the north pole than near the south
pole.
7.
A DC power supply is connected to a coil with an iron core, as shown in the
diagram. What will be the direction of the magnetic field inside the coil, and the
polarity of the coil? _____
(a) from X to Y, with a north pole at X
(b) from X to Y, with a north pole at Y
(c) from Y to X, with a north pole at X
(d) from Y to X, with a north pole at Y
8.
According to domain theory, what will happen to the domains in a ferromagnetic
material placed in a magnetic field whose strength is increased? _____
(a) The alignment of the domains will be reversed.
(b) Less alignment of the domains will take place.
(c) More alignment of the domains will take place.
(d) No change will occur.
9.
Parallel wires X and Y carry electric currents. What will be the result if the
direction of the current in wire X is reversed? _____
(a) The current in wire Y will reverse.
(b) The magnetic forces on both wires will reverse.
(c) The magnetic force on wire X only will reverse.
(d) The magnetic force on wire Y only will reverse.
Copyright © 2003 McGraw-Hill Ryerson Limited.
Date:
Name:
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10. What is the direction of the current induced in the wire as a result of moving
through the magnetic field? What rule is used to determine this direction?
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11. What is the direction of the force exerted by the magnetic field on this current-
carrying wire? What rule is used to determine this direction?
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12. How does the direction of the force exerted by the magnetic field on the wire
relate to the original motion of the wire?
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13. Explain how your answer to question 3 in relation to a generator.
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14. What is Lenz’s law?
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15. If the generator produces a small current, will the armature be easy or hard to
turn? Why?
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16. How does Lenz’s law apply to motors?
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17. Why does placing a mechanical load on a motor cause more current to flow
through the motor?
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Copyright © 2003 McGraw-Hill Ryerson Limited.