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PhySci > Chapters 20-21 > Flashcards

Chapters 20-21 Flashcards

0
Q

The force a magnet exerts on another magnet, on iron or a similar metal, or on moving charges is ______.

A

a magnetic force

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1
Q

20.4 (21.) What solid-state component in a mobile phone maintains proper voltage levels in the circuits?

A

Diodes

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2
Q
  1. (20.1)

What do electric forces between charges depend on?

A

the quantity of charge involved and how far apart the charges are.

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3
Q

The SI unit of resistance is the_______________.

20.2

A

Ohm

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4
Q
  1. (20.1)

Walking across a carpet is an example of charge being transferred by

A

Friction

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6
Q 
30.    21.2
Which of the following is the reason "soft" Iron is used for the cores of electromagnets?
a. It is difficult to magnetize.
b. It is easily magnetized.
c. I has no magnetic domains.
d. It is a permanent magnet.
A

b. It is easily magnetized

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7
Q
  1. (21.3)

The process of generating an electric current by moving an electrical conductor relative to a magnetic field is called

A

electromagnetic induction.

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8
Q
  1. What materials provide electrical safety?

20. 3

A

circuit breaker, fuse and ground-fault circuit interrupter.

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9
Q

The SI unit of resistance is the

A

ohm

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10
Q
  1. (21.3)
    A device that changes mechanical energy to electrical energy by rotating a coil of wire through a magnetic field is called a(an)
A

generator.

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11
Q
  1. Which of the following provides electrical safety?

20. 3

A

all of the above

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12
Q

Potential difference is measured in

A

voltage

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13
Q
  1. A ground-fault circuit interrupter shuts down a circuit if it
    (20. 3)
A

senses unequal currents.

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14
Q
  1. Information sent as patterns and codes in the controlled flow of electrons through a circuit is a(an)
    (20. 4)
A

electronic signal.

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15
Q
  1. If an atom gains electrons, it becomes a
A

negatively charged ion.

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16
Q
  1. The strength of an electric field depends on the
A

The amount of charge that produced the field, and

distance from the charge.

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17
Q
  1. If the two charges represented in Figure 20-1 were brought near each other, they would
A

attract each other.

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18
Q

A ferromagnetic material that has domains that remain aligned for a long period of time is called…

A

A permanent magnet.

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19
Q

How can a permanent magnet be demagnetized?

A

Both B and C; Heating the magnet up, and Striking the magnet with a heavy blow.

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20
Q

If the current in the wire is directed upward, what is the direction of the magnetic field produced by the current?

A

Counterclockwise in the horizontal plane.

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21
Q

The output voltage and current of a transformer are determined by the

A

number of turns in the primary and secondary coils

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22
Q
  1. 21.2

The electromagnet in a galvanometer

A

moves a pointer along a numbered scale in response to a current.

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23
Q
  1. (21.2)

A(an)_______________converts electrical energy into mechanical energy.

A

electric motor

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24
Q
  1. (21.3)

Moving a magnet through a wire coil can produce a(an)_______________in the coil.

A

electric current or voltage

25
49. A(an)_______________signal encodes information as a string of 1's and 0's. (20.4)
digital
26
50. A cathode-ray tube is a type of_______________tube. (20.4)
vacuum
27
32. (21.2) In an electric motor, periodically chaging the direction of current in the electromagnet can cause the axle to spin because
the magnetic field reverses direction.
28
33. (21.3) | Moving a magnet inside a coil of wire will induce a voltage in the coil. How can the voltage in the coil be increased?
Move the magnet inside the coil of wire more rapidly.
29
58. (21.2) When the direction of a current in a wire is reversed, the wire will be deflected perpendicular to the magnetic field in the_______________direction.
Opposite
30
59. (21.2) The strength of a(an)_______________depends on the current in the solenoid, the number of coils, and the type of ferromagnetic material in the core.
Electromagnet
31
13.(20.3) Most of the circuits in your home are
parallel circuits.
32
14.(20.3) What is the unit of electric power?
watt
33
15.(20.3) If you know the power rating of an appliance and the voltage of the line it is attached to, you can calculate the current the appliance uses by
dividing the power by the voltage.
34
6. (20.1) | If a neutral metal comb is held near an object with negative charge, the comb will be charged by
Induction
35
7. (20.2) What material allows charges to flow easily?
an electrical conductor
36
8. (20.2) An electrical insulator has
electrons tightly bound to its atoms.
37
9. (20.2) Resistance is affected by a material's
thickness, length, and temperature.
38
A material that has almost zero resistance when it is cooled to low temperatures is a(an)_______________. 20.2
superconductor
39
10. (20.2) What would reduce the resistance of a metal wire?
increasing its thickness
40
11. (20.2) The current in a hair dryer measures 15.0 amps. The resistance of the hair dryer is 8 ohms. What is the voltage?
120 V
41
12. (20.2) What represents Ohm's law?
V = I * R
42
56. (21.1) | Magnetic domains aligned with an external field get_______________as a ferromagnetic material is magnetized.
larger
43
57. (21.2) | A charged particle moving in a magnetic field will be deflected in a direction_______________to the magnetic field.
perpendicular at right angles
44
33) 20.1 | Like charges____ and opposite charges ____
Repel, attract
45
32) 20.1 | When a pathway through which charges can move forms suddenly,____ occurs.
Static discharge, or electric discharge.
46
68) Name three kinds of solid state components.
Diodes, transistors and integrated circuits.
47
69) 21.3 | Does movement of a conducting wire in a magnetic field always produce a current? Explain your answer.
No; currents a only induced if the conductor is part of a complete circuit.
48
23. (21.1) How does the magnetic force exerted by a magnet change as the distance between two magnets increases?
The magnetic force decreases.
49
19. (20.4) Electronic signals that are smoothly varying signals produced by continuously changing the voltage or current in a circuit are
analog signal.
50
20.(20.4)What do transistors do in a mobile phone?
amplify the phone's incoming signal
51
70.(21.3) How is water used to produce electrical energy in a hydroelectric power plant?
Falling water pushes the blades of a turbine, which turns the axle of a generator or spins magnets around coils of wire.
52
54.（21.1） | The magnetic field lines of a bar magnet begin near the magnet's_______________.
north pole
53
55.（21.1） | The_______________are caused by charged particles from the sun entering Earth's magnetic field.
auroraa
54
40. (2.1) Electric force is _____ proportional to the amount of charge and _____ proportional to the square of the difference between charges.
directly, inversley
55
41. (2.1) Like charges _____ and opposite charges _____.
repel, attract
56
66. (20.1) What is a charge's electric field?
the effect an electric charge has on other charges in the space around it
57
67. (20.4) What are two types of electronic signals, and how is each produced?
Analog signals are produced by continuously varying a voltage or current, and digital signals are produced by turning the current on and off
58
21-3 38. How are step-up transformers used in the transmission of electrical energy?
They increase the voltage and the current for a home.
59
64. Transformers only work with _______ current. | 21-3
Alternating

PhySci (5 decks)

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