MAGNATISM

Magnetic Force

A magnet is a piece of metal that can attract other metallic things such as steel, nickel, and cobalt.

The name comes from magnetis lithos.

Lodestones or magnetites are natural magnets.

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​Magnets

Multiple Choice

magnet means

• A device that stores electrical energy.
• An object that produces a magnetic field.
• A type of metal used in construction.
• An object that repels all other materials.

Multiple Choice

similar pole ..... while different plole....

• Similar poles attract, different poles repel.
• Similar poles attract, different poles neutralize.
• Similar poles neutralize, different poles attract.
• Similar poles repel, different poles attract.

Magnets have two poles - the north pole, and the south pole.

Magnets attract other magnets and metals.

When opposite poles are pointed toward each other, they attract.

When same poles are pointed to each other, they repel.

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​Magnets

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magnet has ... pole

• one pole
• two poles
• three poles
• four poles

​Key Concepts 4- Magnetism

The force that magnets exert is called magnetism.

Magnetism is caused by the magnetic field which is invisible.

The magnetic field is formed around the magnet.

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Magnetism

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magnetic field

• A magnetic field is only present in outer space.
• A magnetic field is a region around a magnetic material or a moving electric charge within which the force of magnetism acts.
• A magnetic field is a solid object that can be touched.
• A magnetic field is a type of electric current.

Multiple Choice

Which one is NOT a natural magnet?

• electromagnet

• lodestone

• magnetite

Multiple Choice

What happens when the North poles of two magnets are pointed twards each other?

• they attract

• they repel

• they produce heat

Multiple Choice

What happens when the North and South poles of two magnets are pointed towards each other?

• they attract

• they repel

• they produce heat

Some materials are nonmagnetic like cloth and plastic.

Materials with iron, nickel, and cobalt can become magnets.

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Magnetic Materials

​Magnetic Fields:​

All magnets are surrounded by a magnetic field. A magnetic field is defined as: The region around a magnet where a force acts on another magnet or on a magnetic material

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Magnetic field lines are used to represent the strength and direction of a magnetic field.

​Magnetic Forces

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Remember this​!

The Magnetic field always comes out of the north pole to the south pole.​

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Multiple Choice

What do the lines around this magnet represent?

• North Pole
• South Pole
• Magnetic Declination
• Magnetic Field

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If you place the North pole of a magnet next to the South pole of another magnet, they will:

• Attract
• Repel
• Do nothing
• Shatter

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A paper clip is an example of a:

• magnetic material
• permanent magnet
• bar magnet
• insulator

Multiple Choice

What happens when two north poles of a magnet are placed together?

• they repel
• they attract
• they cancel each other out
• the strength of the magnet is doubled

Multiple Choice

The strongest part of a magnet is...

• the bars.
• the force field.
• the poles. 
• the middle.

Multiple Choice

All magnets have 2

• fields
• colors
• poles
• all of the above

Multiple Choice

The two poles on a magnet are

• north and east
• north and west
• south and north
• south and west

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What do the lines around this magnet represent?

• North Pole
• South Pole
• Magnetic Declination
• Magnetic Field

Multiple Choice

_{^{The magnet's shown will}}

• not move
• attract
• repel
• all of the above

Multiple Choice

Magnetism is a force of ____________________________ that occurs between two _____________ objects.

• attraction or repulsion, magnetic

• external or internal, magnetic

• external or repulsion, electronic

• attraction or internal, electronic

Multiple Choice

The magnetic ____________ around a bar magnet is shown above.

• legs

• flowers

• field

• direction

Multiple Choice

Certain materials respond to magnetic fields by becoming ______________ themselves. ____________ is one of these materials.

• magnetic, Plastic

• electronic, Iron

• magnetic, Iron

• electronic, Plastic

Magnetic Field

• Around a magnet is a magnetic field (B-field)

  • At every point in space there is a magnetic force

  • Earth's magnetic field can be visialized with a compass

  • Unit for magnetic field: Tesla (T)

• Magnets can be visualized with field lines​.

  • Start at N pole and ends at S pole

  • More lines in one area means a stronger field. ​

Magnetic Field

• Since current (moving charges) make B-fields, then other B-fields apply a force to moving charges

• For a moving charge to experience a force:

  • Charge must be moving

  • The velocity of the charge must have a component perpendicular to the magnatic-field​