Magnetism

Question 1

What is the definition of Magnetic fields?

Answer 1

A region in space where an object (with certain properties) will experience a force.

Question 2

Three objects with (what?) certain properties experience forces in what type of fields?

Answer 2

All objects with mass experience a force of attraction in gravitational fields.

Charged objects experience a force in an electric field.

Magnetised objects and moving charges experience a force in magnetic fields.

Question 3

What type of magnet has strong magnetic fields around it?

Answer 3

Permanent magnet

Question 4

Materials that are attracted to magnets are called …

Answer 4

Magnetic

Question 5

What 3 metals can be magnetised?

Answer 5

Iron (Fe)
Cobalt (Co)
Nickel (Ni)

Question 6

Term for:

Materials that have magnetic properties, can be magnetised and are strongly attracted to metals.

Answer 6

Ferromagnetism / Ferromagnetic

Question 7

Definition of domains

Answer 7

Magnetically aligned regions within ferromagnetic materials.

Question 8

Domains are never randomly arranged. T/F

Domains are the result of many unpaired electrons preferring to stop spinning. T/F

Answer 8

FALSE: Domains are USUALLY randomly arranged.
FALSE: Domains are the result of many unpaired electrons preferring to ALIGN THEIR SPINS.

Question 9

What does it create when magnets have their domains aligned?

Answer 9

A net magnetic field.

Question 10

What can you do to randomise a magnets domains?

Answer 10

Heating it.

Dropping it.

Question 11

Can ferromagnetic materials become

temporary/ permanent magnets?

Answer 11

Yes, by exposing the ferromagnetic material to external magnetic fields. This will align the materials domains parallel to the external magnetic field.

Question 12

Magnets have a … and … pole.

There are monopoles in nature. T/F

The fundamental building blocks of magnets are spinning electrons. T/F

Answer 12

North and South Pole.
FALSE: There are NO monopoles in nature.
TRUE: The fundamental building blocks of magnets are spinning electrons.

Question 13

Where, in the drawing of a magnet, is there a strong magnitude/high density and weak magnitude/low density?

Answer 13

Strong m/High d: As the field lines come out of the North Pole and go into the South Pole.

Weak m/ Low d: Halfway between the North and South poles.

Question 14

Direction of the field lines around and inside a magnet?

Answer 14

Field lines travel from North to South outside the magnet.

And from South to North inside the magnet.

Question 15

Like poles …

Unlike poles …

Answer 15

Like poles repel.

Unlike poles attract.

Question 16

If the Earth was a bar magnet the Earths geographical North Pole is a bar magnets … Pole.

Answer 16

Earths geographical North is a bar magnets South Pole.

Question 17

Is Earths geographical North Pole the same as the Magnetic North Pole?

Answer 17

No, there’s 11.5 degrees different.

Earths geographical North Pole we call true North.

Question 18

What is magnetic flux?

Answer 18

The number of field lines drawn crossing a given two dimensional surface.
It is used to measure the strength of the magnetic field.

Question 19

What is formed when the magnetosphere deflects the solar wind which then collides with the atmosphere.

Answer 19

Aurora Australis

Question 20

Explain the domain theory of magnetism…

Answer 20

Electrons spin so that atoms in ferromagnetic materials behave like small magnets, these “magnets” magnetic fields point in all directions.
When they become aligned they form small regions of stronger magnetism, called magnetic domains.
When all the domains are magnetically aligned the subject as a whole becomes magnetized.

Question 21

Briefly explain what happens when two metal spheres with different charges are brought together.

Answer 21

Electrons are transferred between the spheres during
contact and the spheres acquire equal like
charges and therefore repel each-other.

Question 22

Define the Voltage of a battery.

Answer 22

The total energy provided by the cell per

unit charge.

Question 23

How do we create permanent/temporary magnets?

Answer 23

By exposing ferromagnetic materials to external magnetic fields.