Magmetism

Question 1

what is the law of magnetic force

Answer 1

like poles repel
unlike poles attract

Question 2

what is magnetism?

Answer 2

movement of electrical charge, caused by electrons moving inside atoms, creating magnetic fields all around them. it is caused by a change in electrical current

Question 3

what does the force of attraction depend on

Answer 3

• strength of individual magnetic poles
• distance separating them and the material
• medium occupying the space between them

Question 4

can a magnet exist on its own

Answer 4

NO

Question 5

what is the domain theory

Answer 5

• all large magnets are made up of magnetic regions
• domains originate from dipoles which interact with neighbouring dipoles if they align in one direction then a large magnetic domain is produced.

Question 6

what is a magnetic dipole

Answer 6

a magnet which causes the flow of charge

Question 7

how does alignment occur with dipoles?

Answer 7

electrons circulate around the nucleus, with them spinning on their axes. The dipoles are arranged randomly with no magnetic effect

Question 8

what is diamagnetism?

Answer 8

• possess no inherent dipoles
• the relative permeability is less than 1 (induced magnetism)
• a loss of alignment is caused by the removal of an external field, with no residual alignment remains
• effects are weak
• electrons are get distorted by an external magnetic force

Question 9

what does magnetisation depend on?

Answer 9

atomic dipoles, which arise from various orbitals and the spinning magnetic moments of atomic electrons

Question 10

what is paramagnetism?

Answer 10

inherent magnetisation from the spin and orbital electrons around the nucleus which is destroyed rapidly, once the external field is removed. This alignment is destroyed by the background internal energy in the material.
When an electrical field is applied it causes the alignment of the magnets becoming magnetised, this is weak.

Question 11

what is ferromagnetism?

Answer 11

it is when a strong magnetic force is applied, causing a strong alignment of the domains increasing the magnetisation force. Beyond this will not causes an increase in magnetisation. Once this force is removed, there is still a residual magnetism due to some of the domains being still aligned.

contain a group of aligned atomic dipoles = domains

Question 12

what is the orientation of the domains

Answer 12

randomly

Question 13

what happens to permanent magnets?

Answer 13

they retain magnetism for a long time, the domains find it difficult for a change of alignment once facing each other

Question 14

what happens to temporary magnets?

Answer 14

once influenced by permanent magnets, once this is taken away the domains return to its random alignment (free to rotate)

Question 15

what is a magnetic field

Answer 15

an area around a magnet in which the magnetic effect is noticed

Question 16

what is a coercive force

Answer 16

a reversed magnetic force which needs to be applied in order to destroy the alignment of domains and achieve complete demagnetisation

Question 17

what is a line of force

Answer 17

path which is taken by an independent North Pole, moving from north to South Pole, this can be obseverved

Question 18

what is magnetic influx

Answer 18

it is the total number of lines which expresses the poles strength, flux density represents the magnetic flux

Question 19

is a horse shoe magnet more advantageous

Answer 19

it has a greater field strength, as the poles are closer, by adding specially shaped soft iron pieces we can produce a magnetic field, in which most lines are parallel to eachother

Question 20

where does lines of force originate

Answer 20

from north and ends at south, these lines don’t cross
the strength is greater at the poles (more concentrated)

Question 21

what happens when a ferromagnetic object is placed in a magnetic field?

Answer 21

the lines become concentrated, intensifying the flux density within and around