Please help I don't know this stuff
Question 1
Marks: 1
A step-up transformer increases
Choose one answer.
a. energy.
b. power.
c. both A and B
d. none of the above
Question 2
Marks: 1
A device that transforms electrical energy to mechanical energy is a
Choose one answer.
a. generator.
b. transformer.
c. magnet.
d. motor.
e. none of the above
Question 3
Marks: 1
Just as it is easy to separate electric charges, it is relatively easy to isolate a magnet’s poles.
Answer:
True False
Question 4
Marks: 1
In order to make an electromagnet, you need a
Choose one answer.
a. battery, a nail, and a magnet.
b. battery, some wire, and a nail.
c. loop of wire, contacts, and a battery.
d. magnet, a nail, and some wires.
e. none of the above
Question 5
Marks: 1
The principal advantage of AC power over DC power is that
Choose one answer.
a. AC voltage oscillates, whereas DC voltage does not.
b. lower voltages are used.
c. AC circuits multiply power more easily.
d. AC voltage can be transformed more easily.
e. AC circuits are safer.
Question 6
Marks: 1
A device consisting of a coil that is mechanically rotated in a stationary magnetic field is called
Choose one answer.
a. a motor.
b. a magnetic pole.
c. a generator.
d. a transformer.
e. a dipole.
Question 7
Marks: 1
There is a magnetic field around a current-carrying wire.
Answer:
True False
Question 8
Marks: 1
Almost all energy sold today is of the AC type because
Choose one answer.
a. DC voltages dont last.
b. DC energy wastes electricity.
c. AC voltage is easy to step up and step down.
d. AC energy was established first.
Question 9
Marks: 1
An electric motor and an electric generator are
Choose one answer.
a. entirely different devices.
b. very similar devices.
Question 10
Marks: 1
A certain transformer doubles input voltage. If the primary coil has 12 A of current, then the current in the secondary coil is
Choose one answer.
a. 2 A.
b. 6 A.
c. 12 A.
d. 24 A.
e. none of the above
Question 11
Marks: 1
A step-up transformer has a ratio of 1:10. If 200 W of power goes into the primary coil, the power coming from the secondary coil is approximately
Choose one answer.
a. 2 W.
b. 20 W.
c. 200 W.
d. 2000 W.
e. more than 2000 W.
Question 12
Marks: 1
The primary coil of a transformer has 100 turns on it and the secondary coil has 50 turns on it. This is
Choose one answer.
a. a step-down transformer.
b. a step-up transformer.
c. either of the above, depending on relative input and output currents
Question 13
Marks: 1
A step-up transformer
Choose one answer.
a. doesnt change the voltage at all.
b. decreases voltage.
c. increases voltage.
Question 14
Marks: 1
Magnetic domains are
Choose one answer.
a. regions that may or may not be magnetized.
b. clusters of atoms randomly aligned.
c. regions of atoms magnetically aligned.
d. blocks of material.
Question 15
Marks: 1
Loops of wire in a motor rotate because a
Choose one answer.
a. battery effectively pushes a loop around in the field.
b. current exerts a force on the loop, causing it to rotate.
c. magnetic field exerts forces on moving electrons in the loop.
d. magnet attracts stationary electrons in the wire.
e. none of the above
Question 16
Marks: 1
If the north pole of one magnet is brought near the south pole of another magnet, the poles will
Choose one answer.
a. repel each other.
b. attract each other.
c. not interact with each other at all.
Question 17
Marks: 1
If you break a bar magnet in half, each half
Choose one answer.
a. becomes a bar magnet with two poles.
b. becomes unmagnetized.
c. contains one magnetic pole.
Question 18
Marks: 1
A transformer works because
Choose one answer.
a. electricity flows from a primary coil to a secondary coil.
b. electricity is induced in a rotating coil.
c. a changing magnetic field is transferred to a coil via an iron core.
d. electricity is transferred to a coil via an iron core.
Question 19
Marks: 1
Magnetic field strength is
Choose one answer.
a. strongest close to a magnet.
b. constant everywhere around a magnet.
c. strongest far from a magnet.
Question 20
Marks: 1
A transformer transforms
Choose one answer.
a. magnetic field lines.
b. generators into motors.
c. voltage.
d. unsafe forms of energy into safe forms.
Question 1
Marks: 1
A step-up transformer increases
Choose one answer.
a. energy.
b. power.
c. both A and B
d. none of the above
Question 2
Marks: 1
A device that transforms electrical energy to mechanical energy is a
Choose one answer.
a. generator.
b. transformer.
c. magnet.
d. motor.
e. none of the above
Question 3
Marks: 1
Just as it is easy to separate electric charges, it is relatively easy to isolate a magnet’s poles.
Answer:
True False
Question 4
Marks: 1
In order to make an electromagnet, you need a
Choose one answer.
a. battery, a nail, and a magnet.
b. battery, some wire, and a nail.
c. loop of wire, contacts, and a battery.
d. magnet, a nail, and some wires.
e. none of the above
Question 5
Marks: 1
The principal advantage of AC power over DC power is that
Choose one answer.
a. AC voltage oscillates, whereas DC voltage does not.
b. lower voltages are used.
c. AC circuits multiply power more easily.
d. AC voltage can be transformed more easily.
e. AC circuits are safer.
Question 6
Marks: 1
A device consisting of a coil that is mechanically rotated in a stationary magnetic field is called
Choose one answer.
a. a motor.
b. a magnetic pole.
c. a generator.
d. a transformer.
e. a dipole.
Question 7
Marks: 1
There is a magnetic field around a current-carrying wire.
Answer:
True False
Question 8
Marks: 1
Almost all energy sold today is of the AC type because
Choose one answer.
a. DC voltages dont last.
b. DC energy wastes electricity.
c. AC voltage is easy to step up and step down.
d. AC energy was established first.
Question 9
Marks: 1
An electric motor and an electric generator are
Choose one answer.
a. entirely different devices.
b. very similar devices.
Question 10
Marks: 1
A certain transformer doubles input voltage. If the primary coil has 12 A of current, then the current in the secondary coil is
Choose one answer.
a. 2 A.
b. 6 A.
c. 12 A.
d. 24 A.
e. none of the above
Question 11
Marks: 1
A step-up transformer has a ratio of 1:10. If 200 W of power goes into the primary coil, the power coming from the secondary coil is approximately
Choose one answer.
a. 2 W.
b. 20 W.
c. 200 W.
d. 2000 W.
e. more than 2000 W.
Question 12
Marks: 1
The primary coil of a transformer has 100 turns on it and the secondary coil has 50 turns on it. This is
Choose one answer.
a. a step-down transformer.
b. a step-up transformer.
c. either of the above, depending on relative input and output currents
Question 13
Marks: 1
A step-up transformer
Choose one answer.
a. doesnt change the voltage at all.
b. decreases voltage.
c. increases voltage.
Question 14
Marks: 1
Magnetic domains are
Choose one answer.
a. regions that may or may not be magnetized.
b. clusters of atoms randomly aligned.
c. regions of atoms magnetically aligned.
d. blocks of material.
Question 15
Marks: 1
Loops of wire in a motor rotate because a
Choose one answer.
a. battery effectively pushes a loop around in the field.
b. current exerts a force on the loop, causing it to rotate.
c. magnetic field exerts forces on moving electrons in the loop.
d. magnet attracts stationary electrons in the wire.
e. none of the above
Question 16
Marks: 1
If the north pole of one magnet is brought near the south pole of another magnet, the poles will
Choose one answer.
a. repel each other.
b. attract each other.
c. not interact with each other at all.
Question 17
Marks: 1
If you break a bar magnet in half, each half
Choose one answer.
a. becomes a bar magnet with two poles.
b. becomes unmagnetized.
c. contains one magnetic pole.
Question 18
Marks: 1
A transformer works because
Choose one answer.
a. electricity flows from a primary coil to a secondary coil.
b. electricity is induced in a rotating coil.
c. a changing magnetic field is transferred to a coil via an iron core.
d. electricity is transferred to a coil via an iron core.
Question 19
Marks: 1
Magnetic field strength is
Choose one answer.
a. strongest close to a magnet.
b. constant everywhere around a magnet.
c. strongest far from a magnet.
Question 20
Marks: 1
A transformer transforms
Choose one answer.
a. magnetic field lines.
b. generators into motors.
c. voltage.
d. unsafe forms of energy into safe forms.