Electromagnetic Induction
Practice Test
1.
A 75.0 W lightbulb is 25.0% efficient. How many joules of thermal energy does the lightbulb produce each minute?
a.
563 J
b.
4500 J
c.
3380 J
d.
1130 J
Hint
2.
A beam of protons travels at 3.5 × 10E6 m/s through a uniform magnetic field of 5.7×10
-2
T. The beam of electrons is perpendicular to the field. How strong is the force acting on each proton?
a.
1.6×10
-12
N
b.
3.2×10
-14
N
c.
3.2×10
-12
N
d.
-6.4×10
-14
N
Hint
3.
A positive test charge of 9.0 × 10
-5
" to "9.0×10
-5
C is in an electric field that exerts a force of 3.7×10
-5
N on it. What is the magnitude of the electric field at the location of the test charge?
a.
0.24 N/C
b.
4.1 N/C
c.
2.4 N/C
d.
0.41 N/C
Hint
4.
A changing magnetic field can produce a(n)__________.
a.
spark of electricity
b.
resistor
c.
electric current
d.
force
Hint
5.
A 0.30-m long straight wire moves at a constant speed of 9.5 m/s perpendicular to a magnetic field of strength 0.083 T. What
EMF
is induced in the wire?
a.
1.2 V
b.
2.6 V
c.
0.48 V
d.
0.24 V
Hint
6.
An electric field is to be measured using a positive test charge of 3.0×10
-5
C. This test charge experiences a force of 0.50 N acting at an angle of 15°. What is the magnitude of the electric field at the location of the test charge?
a.
0.49 N/C
b.
6.0×10
-5
N/C
c.
1.7×10
3
N/C
d.
1.7×10
4
N/C
Hint
7.
Touching a body to Earth to eliminate excess charge is called __________.
a.
grounding
b.
capacitance
c.
resistance
d.
static
Hint
8.
The force on an electron from a magnetic field is __________.
a.
so small it cannot be measured
b.
in the same direction as indicated by the third right hand rule
c.
in the same direction as the magnetic field
d.
opposite the direction indicated by the third right hand rule
Hint
9.
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.
0.06 Ω
c.
30 Ω
d.
5.4 Ω
Hint
10.
If the charge of an atom's nucleus is +2 and the charge of the surrounding electrons is -2, the atom is __________.
a.
positively-charged
b.
unstable
c.
electrically neutral
d.
negatively-charged
Hint
11.
A south pole will __________ another south pole.
a.
repel
b.
destroy
c.
attract
d.
ignore
Hint
12.
If the ammeter in Figure 22-3 were moved to the left of the light bulb, what would it read?
a.
1 A
b.
2 A
c.
4 A
d.
0 A
Hint
13.
In Figure 25-13a, if the primary coil were increased to 10 turns while its voltage and current were kept the same, what effect would this have on the secondary coil?
a.
Its number of turns would increase.
b.
Its current would decrease.
c.
Its power would increase.
d.
Its voltage would decrease.
Hint
14.
If a positively-charged glass rod is suspended so that it turns easily, and another positively-charged glass rod is brought close to it, the two rods will __________.
a.
repel each other
b.
not react
c.
attract each other
d.
fuse
Hint
15.
Thermal energy is given by:
a.
E
=
Pt
b.
E
=
IR
c.
E
=
I
2
R
d.
E
=
P
2
t
Hint
16.
If you increase the distance between two charges, what happens to the force?
a.
It vanishes.
b.
It increases.
c.
It decreases.
d.
It stays the same.
Hint
17.
How far apart are two electrons if they exert a force of repulsion of 2.5 N on each other?
a.
9.6 × 10
15
m
b.
9.6 × 10
-15
m
c.
1.5 × 10
-14
m
d.
1.6 × 10
-19
m
Hint
18.
Electric potential difference is measured in __________.
a.
volts per coulomb
b.
newtons per coulomb
c.
coulombs per joule
d.
joules per coulomb
Hint
19.
A nail that touches a magnet will __________.
a.
generate an electric current
b.
become polarized
c.
melt
d.
demagnetize the magnet
Hint
20.
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.
3.25 A
c.
0.520 A
d.
7.75 A
Hint
