Electromagnetism
Practice Test
1.
What is the equation to find current in a series of three resistors?
a.
I
=
V
/(
R
1
×
R
2
×
R
3
)
b.
I
=
V
/(
R
1
+
R
2
+
R
3
)
c.
I
=
V
(
R
1
+
R
2
+
R
3
)
d.
I
=
V
(
R
1
×
R
2
×
R
3
)
Hint
2.
__________ is the generation of current due to relative motion between a wire and a magnetic field.
a.
Magnetic flux
b.
Electromagnetic induction
c.
Electrospectrometry
d.
Electrolysis
Hint
3.
A step-up transformer has 400 turns on its primary coil and 1000 turns on its secondary coil. If the secondary coil has a current of 1.30 A, what is the current in the primary coil?
a.
1.62 A
b.
0.520 A
c.
7.75 A
d.
3.25 A
Hint
4.
For the circuit arrangement shown in Figure 22-4, if the battery voltage is 9.0 V and the ammeter reads 0.60 A, what is the resistance?
a.
15 Ω
b.
30 Ω
c.
0.06 Ω
d.
5.4 Ω
Hint
5.
A magnetic field is generated __________ the direction of current in a wire.
a.
in the same direction as
b.
opposite of
c.
perpendicular to
d.
parallel to
Hint
6.
Combined electric and magnetic fields that move through space are called __________.
a.
radiation waves
b.
electromagnetic waves
c.
oscillating fields
d.
piezoelectric fields
Hint
7.
If the average power dissipated by an electric light is 75 W, what is the maximum power?
a.
100 W
b.
150 W
c.
75 W
d.
50 W
Hint
8.
A magnetic field exerts a force on __________.
a.
only electrons
b.
only small particles
c.
all charged particles, regardless of size
d.
only wires
Hint
9.
A 12.0 V battery delivers a 1.20 A current to an electric motor that is connected across terminals. What power is consumed by the motor?
a.
14.4 W
b.
10.0 J
c.
10.0 W
d.
14.4 J
Hint
10.
Why does running too many appliances on one circuit cause a fuse to blow or a circuit breaker to shut off?
a.
As more resistors are added in parallel, the total resistance decreases, which causes an increase in the total amount of voltage.
b.
The current drops to almost zero.
c.
As more resistors are added in parallel, the total resistance decreases, which causes an increase in the total amount of current.
d.
The voltage becomes too much for the circuit to handle.
Hint
11.
In the river model for an electric circuit, the amount of water flowing through the river each second is the __________.
a.
power
b.
current
c.
path
d.
voltage
Hint
12.
If the combined resistance of the potentiometer and motor in Figure 22-5 is 250 Ω, what is the current through the circuit?
a.
3000 A
b.
21 A
c.
120 A
d.
48 mA
Hint
13.
In a transformer, the primary coil has twice as many loops as the secondary coil. This is a __________ transformer.
a.
reduction
b.
voltage
c.
step-up
d.
step-down
Hint
14.
A south pole will __________ another south pole.
a.
ignore
b.
attract
c.
repel
d.
destroy
Hint
15.
What happens when an electric switch is turned off?
a.
The circuit becomes a series circuit.
b.
A circuit breaker turns off.
c.
There is a short circuit.
d.
The circuit is broken.
Hint
16.
The __________ is used to determine the charge-to-mass ratio of gases.
a.
mass spectrometer
b.
cathode-ray tube
c.
antenna
d.
electron microscope
Hint
17.
The charge-to-mass ratio of an electron in a Thomson tube is represented by the equation __________.
a.
m
/
q
=
v
/
Br
b.
q
/
m
=
Br
/
v
c.
q
/
m
=
v
/
Br
d.
q
/
m
=
Bqv
Hint
18.
A receiver is a combination of ____________.
a.
an antenna and an amplifier
b.
a coil and capacitor circuit
c.
an antenna, a coil and capacitor circuit, and an amplifier
d.
an antenna, a capacitor circuit, and a resonator
Hint
19.
The second right hand rule is used to determine the __________.
a.
direction of current
b.
direction of the magnetic field
c.
direction of magnetic force
d.
amount of current
Hint
20.
What is a superconductor?
a.
a meterial with a very high resistance
b.
a powerful battery
c.
a material with zero resistance
d.
a magnet
Hint
