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Physics: Grade 11 > Unit 1: Magnets & Electricity > Flashcards

Unit 1: Magnets & Electricity Flashcards

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1
Q

Magnet:

A

An object that produces a magnetic field

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2
Q

What materials do magnets attract?

A

Ferromagnetic materials

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3
Q

List some ferromagnetic materials:

A

Iron, nickel, cobalt and alloys of them

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4
Q

Opposite poles….

A

Attract

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5
Q

Like poles….

A

Repel

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6
Q

Define ferromagnetic:

A

The ability to be magnetized

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7
Q

Magnetic field:

A

The distribution of a magnetic force in the region of a magnet

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8
Q

Demagnetizations occurs when:

A

When a magnet is physically disrupted or heated to a very high temp

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9
Q

What are the small magnets called within magnets:

A

Dipoles

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10
Q

What do dipoles do in the material:

A

React with other dipoles

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11
Q

The dipoles in a demagnetized material face:

A

Random directions

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12
Q

If the dipoles line up in a single direction:

A

Small magnetic domains are created

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13
Q

Where do dipoles face in a magnetized material

A

The same direction

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14
Q

What do the domains do in a strong magnetic field:

A

They line up forming 1 large magnet

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15
Q

What does breaking a magnet in 2 cause?:

A

It causes the domains to remain aligned & 2 new magnets are formed

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16
Q

How does demagnetization happen:

A

When u disrupt the alignment of the domains so the dipoles are randomly distributed

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17
Q

Soft ferromagnetic:

A

Remains magnetic only in the presence of a magnetic field

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18
Q

What does a soft ferromagnetic material have:

A

Low loss and high permeability

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19
Q

Why does a soft ferromagnetic material lose magnetism quick?:

A

Bc domains inside can be aligned very easily

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20
Q

What magnets are soft ferromagnetic materials used for?

A

Temporary magnets

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21
Q

Hard ferromagnetic materials:

A

Remains magnetic after the magnetic field has been removed.

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22
Q

What do hard ferromagnetic materials do?:

A

They strongly resist demagnetization once magnetized

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23
Q

What are hard ferromagnetic materials used for:

A

Permanent magnets

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24
Q

Oersteds principle is by:

A

Hand Christine oersted conducted 1820

25
Q

Oersteds principle says:

A

Electricity moving through a conductor produces a circular magnetic field around the conductor

26
Q

Electromagnetism:

A

A combo of 2 words - electricity and magnet

27
Q

What affects the field strength:

A

Number of coils & permeable core

28
Q

Which way does a conventional current flow?

A

(+) to (-)

29
Q

Which way does an electron current flow:

A

(-) to (+)

30
Q

What is the motor principle: pt 1.

A

When a I carrying conductor is placed in an (external) B field, the conductor experiences a force perpendicular to itself and the magnet

31
Q

What happens next in the motor principle? pt.2

A

When electricity is turned on, I flows though a wire. The wire experiences a force causing it to move in a direction perpendicular to the magnetic field

32
Q

Why does the motor principle work?

A

(Beginning of oersteds principle) therefore when brought near a wife, the magnet either attracts or repels the wife depending on N &S

33
Q

Explanation of motor principle:

A

2 fields cause the wire to experience force

34
Q

B field produced by current carrying conductor interacts with:

A

The external magnetic field of the magnet

35
Q

Faradays law:

A

Moving or changing the strength of a magnetic field near a conductor cause I to flow in the conductor

36
Q

How do the # of coils affect the current?:

A
  • tightness and compacted wires

- more turns –> greater current

37
Q

How does change of motion (greater or smaller) (of the inducing magnetic field) affect current:

A

Greater rate –> greater induced current

38
Q

How does the strength of the inducing magnetic field affect the current:

A

Greater magnetic field strength –> greater induced current

39
Q

What are transformers used for:

A

To change (transform) voltages from 1 value to another. Used to step up or step down voltages

40
Q

Where are transformers used and why:

A

In primary generations stations so electricity can travel long distances with little energy loss + low current flow

41
Q

Why is it safe to use a transformer:

A

Transformers convert electricity to your neighborhood and step down to you home to use safely

42
Q

Transformer explanation:

A

The AC in the P cool produces a changing magnetic field around the coil which induces a current in the S

43
Q

Why is he energy equal in the transformer coils?:

A

Bc energy cannot be created or destroyed

44
Q

What does moving a magnetic field do?

A

Causes electrons to move

45
Q

What does changing a magnetic field do?

A

Generates current

46
Q

1st step of a transformer:

A

A p & s coil are connected to a core of ferromagnetic material.

47
Q

2nd step of a transformer:

A

Electricity runs though the p cool which generates a magnetic field (an electromagnet is created)

48
Q

3rd step of a transformer:

A

The electromagnet alternates back and forth. An electric current is induced near a word due to the b filed back and forth

49
Q

4th step of a transformer:

A

Electricity is passed from one coil to another (which aren’t touching)

50
Q

5th step of a transformer:

A

Electric field passes through a magnetic field

51
Q

What does he primary coil do?

A

Generates magnetic field

52
Q

What does a secondary coil do?

A

Converts magnetic field to current flow

53
Q

Electricity production:

A

Power plant, turbine, step up transformer, transmission lines, step down transformer, house

54
Q

Benefits of electromagnet:

A

B field can b changed quickly by controlling the amount of electricity, control of magnetic strength, greater magnet power

55
Q

What is a turbine:

A

Wind turns around a 3 propeller blade to a rotor which is connected to the main shaft, which spins + generates electricity.

56
Q

How does a generator work?:

A

A generator is a device that converts mechanical energy (from an external source) to electrical energy

57
Q

Principle of a generator:

A

Faradays law

58
Q

Transmission lines:

A

Sets of wires that Carry electricity from generating plants to a substation that steps the electricity down.

Physics: Grade 11 (4 decks)

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