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Holt Science And Technology > Chapter 18: Electromagnetism > Flashcards

Chapter 18: Electromagnetism Flashcards

1
Q

How many poles do magnets have? Where will they rotate if allowed to rotate freely?

A
  • 2 poles (north and south)

- north will always point north if allowed to rotate freely

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2
Q

What do like and opposite poles do?

A

Like Poles: Repel

Opposite Poles: Attract

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3
Q

What can you make visible by sprinkling iron fillings around a magnet?

A

The magnetic field lines

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4
Q

What are the 2 types of magnets?

A
  • Ferromagnets

- Electromagnets

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5
Q

Why does Earth act as a big bar magnet? Where are it’s magnetic poles located?

A
  • it acts as a big bar magnet through its core/center

- north poles of a magnet point to earths magnetic South Pole (Earths geographic North Pole)

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6
Q

One of two points, such as the ends of a magnet, that have opposing magnetic qualities

A

Magnetic pole

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7
Q

Region around a magnet in which magnetic forces act

A

Magnetic field

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8
Q

Name 3 actions that can cause a magnet to lose its magnetic properties

A
  1. Dropping or hitting it
  2. Putting it in a strong opposite magnetic field
  3. Increasing the temperature
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9
Q

What are Earth’s magnetic poles?

A

Magnetic fields made from electric charges because of the flow of the outer core.

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10
Q

Compare the type and location of Earths magnetic and geographic poles

A

North geographic=South Magnetic

South geographic=North Magnetic

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11
Q

Why are Auroras most commonly seen near Earths magnetic poles?

A

•because Earths magnetic poles bend onward at the poles so the charges particles can crash I TO the atmosphere
•charged particles from the sun hit oxygen and nitrogen atoms in the air
-atoms move faster and give off light of many colours

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12
Q

Name 3 properties of magnets

A
  1. Two poles
  2. Magnetic Forces
  3. Magnetic Fields
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13
Q

How are temporary magnets different from permanent magnets?

A

Temporary: made out of material that is easy to magnetize but loses magnetism easily

Permanent: difficult to magnetize but keeps magnetic properties

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14
Q

Why are some iron objects magnetic while others are not?

A

The ones that are magnetic have their domains lines up while the ones that are not magnetic do not.

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15
Q

What did Oersted discover?

A

A wire carrying a current makes an electric field

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16
Q

The interaction between electricity and magnetism

A

Electromagnetism

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17
Q

What is an electromagnet?

A

A solenoid with a soft, iron core

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18
Q

What does a magnet do to a wire carrying a current?

A

Exert a force on the wire

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19
Q

Three examples of electromagnetism

A
  1. Doorbell
  2. Electric Motor
  3. Galvinometer
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20
Q

A coil of wire with an electric current in it

A

Solenoid

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21
Q

A device that converts electrical energy into mechanical energy

A

Electric motor

22
Q

How can you make an electromagnet become a solenoid?

A

Increasing the electric current in the wire.

23
Q

Name two ways the magnetic field of a solenoid can be increased

A
  1. Adding more loops

2. Increasing the current

24
Q

What is the relationship between an electric current and a magnetic field

A

As electric current increases, the stronger the magnetic field is and vice versa

25
What do Hans Christian Oersteds experiments have to do with a galvanometer?
He concluded that an electric current produces a magnetic field and he needed the galvanometer to measure the electric current
26
What is electromagnetic induction?
The process of making electric current by changing a magnetic field
27
How does a galvanometer make use of the relationship between electric current and magnetic fields?
Galvanometers USE magnets to detect current
28
What does a step up transformer and a step down transformer do?
Step up: Increases voltage/decreases current Step down: Decreases voltage/ increases current (Of an alternating current)
29
Which side of a transformer has higher voltage
The side with a greater number of loops
30
The process of creating a current in a circuit by changing a magnetic field
Electromagnetic induction
31
A divide that converts mechanical energy into electrical energy
Electric generator
32
A device that increases or decreases the voltage of alternating current
Transformer
33
Compare the function of an electric generator with the function of an electric motor
Generator: device that converts mechanical energy into electrical energy Motor: device that converts electrical energy into mechanical energy
34
Compare a step up transformer with a step down based on # of loops in primary and secondary coils
Step up: more coils on secondary Step down: more coils on primary
35
What is one way the discovery of magnetism and the invention of the compass affected our ability to explore the earth
It allowed us to know what direction we are walking and gave us the ability to map out things based off of their relation to each other
36
Explain how the alternating current in the primary coil of a transformer causes a current to be produced in the secondary coil
The primary coil gets an alternating current from an electrical energy source. The current makes the ring into an electromagnet, but the current in the primary coil is alternating. The magnetic field of the electromagnet changes direction as the current changes. The changing magnetic field in the iron ring induces a current in the secondary coil.
37
Any material that attracts iron or materials containing iron is
A magnet
37
Whether a material is magnetic or not depends on _________.
The materials atoms.
37
What is created when a magnet moves through a coil of wire?
An electric current
38
What 2 THINGS strengthen a magnetic field by a current-carrying wire?
1. Electric Motor | 2. Electromagnet
39
What did Faraday's experiments with magnets and electromagnetic induction demonstrate?
Magnetic fields are made when the electric field changes.
40
Electric current that changes direction is called
Alternating current
41
What are three sources of energy that are used to generate electrical energy?
1. Nuclear Energy 2. Fossil Feuls 3. Wind
42
The attraction or repulsion created by spinning electric charges
Magnetic force
43
Groups of atoms in tiny areas of a magnet
Domains
44
The region surrounding the earth in which its magnetic field is the predominant effective magnetic field
Magnetosphere
45
In the region around a magnet in which magnetic forces act exists the _____.
Magnetic poles
46
An electric fan has an electric motor inside to change _____ to ______.
Electrical energy into mechanical energy
47
The marked end of a compass needle always points directly to
A magnet's South Pole
48
What do you end up with if you cut a magnet in half?
Two pieces each with a North Pole and a South Pole

Holt Science And Technology (2 decks)

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