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WorksheetsElectricity and Magnetism 3
Total questions: 20
Worksheet time: 23mins
Name
Class
Date
1.
The magnetic field of an electromagnet can be increased by
a)
changing the direction of the current.
b)
decreasing the current.
c)
increasing the number of coils.
d)
decreasing the number of coils.
2.
What does this illustration represent?
a)
magnetic material that is not magnetized
b)
magnetic material that is magnetized
c)
non-magnetic material
d)
arrangements of atoms in a domain
3.
In this illustration, the magnetic field is strongest ___.
a)
near either pole
b)
near the north pole
c)
near the south pole
d)
halfway between the poles
4.
What effect does increasing the current flowing in the wire have on an electromagnet?
a)
It decreases the strength of the magnetic field.
b)
It increases the strength of the magnetic field.
c)
It has no effect on the electromagnet.
d)
It causes it to become a permanent magnet.
5.
You observe that magnets A and B are attracted to each other and "stick." Which sentence BEST explains this observation?
a)
Both are positively charged.
b)
Both are tightly bonded to each other.
c)
Both are composed of smaller, individual magnets.
d)
Both have all their magnetic domains aligned in the same direction.
6.
As electrons flow through the metal wire in the center of this motor, the metal begins to turn. This is because
a)
electric charges act as tiny magnets.
b)
a flow of electrons experiences a force in a magnetic field.
c)
positive electric charges are attracted to the south pole of a magnet.
d)
positive electric charges are attracted to the north pole of a magnet.
7.
Objects that keep their magnetic properties for a long time are called ___.
a)
electromagnets
b)
magnetic domains
c)
permanent magnets
d)
temporary magnets
8.
A coil of wire with a current is called a(n)
a)
insulator.
b)
solenoid.
c)
electromagnet.
d)
galvanometer.
9.
The function of an electric motor is to change ___.
a)
chemical energy to electrical energy
b)
electrical energy to chemical energy
c)
electrical energy to mechanical energy
d)
mechanical energy to electrical energy
10.
A coil of wire that has a soft iron core and that acts as a magnet when an electric current is in the coil called a(n)
a)
ferromagnet.
b)
electromagnet.
c)
permanent magnet.
d)
temporary magnet.
11.
The primary coil of of a step-up transformer has ten turns and its secondary coil has 100 turns. What is the voltage in the secondary coil if the input voltage in the primary coil is 50 V?
a)
5,500 V
b)
5,000 V
c)
500 V
d)
150 V
12.
Which of the following best describes how electricity is generated for homes?
a)
The spinning of a windmill's blades creates electric current without a generator.
b)
Nuclear reactions cause electric current to flow around the reaction chamber.
c)
Steam pushes turbine blades in a generator, which changes the mechanical energy into an electric current.
d)
Water released from a dam generates electric current, which is transformed into mechanical energy.
13.
When a wire with a current is placed in a magnetic field,
a)
electrical energy is transformed into mechanical energy.
b)
mechanical energy is transformed into electrical energy.
c)
the wire becomes a permanent magnet.
d)
the current stops.
14.
The process of generating an electric current from the motion of a conductor in a magnetic field is
a)
conduction.
b)
induction.
c)
motion.
d)
magnetism.
15.
Electric current from a generating plant is
a)
direct current transmitted at high voltages, but usually used at low voltages.
b)
alternating current transmitted at high voltages, but usually used at low voltages.
c)
alternating current transmitted at low voltages, but usually used at high voltages.
d)
direct current transmitted at low voltages, but usually used at high voltages.
16.
In an electric motor, a commutator
a)
is made out of dozens of wire loops wrapped around a ferromagnetic core.
b)
repeatedly reverses the flow of current through the armature.
c)
is a magnet.
d)
is directly connected to the current source.
17.
Which of the following is a form of electromagnetic induction?
a)
changing electrical energy to mechanical energy that produces sound
b)
producing mechanical energy by sending electric current through an electromagnet
c)
using an electromagnet to measure electric current
d)
producing electric current by moving a magnet through a wire loop
18.
The primary coil (plug end) has twenty turns and the secondary coil (light) has two turns. What is the voltage at the lamp?
a)
15 V
b)
120 V
c)
12 V
d)
1,200 V
19.
The primary coil (plug end) has twenty turns and the secondary coil (light) has two turns. What is the current at the lamp?
a)
12 A
b)
15 A
c)
96 A
d)
1.5 A
20.
Electric current should pass through a ___ after being transmitted by a power plant and before it enters your home.
a)
step-up transformer
b)
generator
c)
turbine
d)
step-down transformer
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