magnet

Describe magnet

Magnet has got 2 ends called poles

North and south

Each magnet exerts a force on on other magnet

Describe forces of a magnet

Magnet can exert a

repulsive force which is between two same poles so

N and N and between S and S

Attractive force between two different poles do N and S or S and N

What happens with poles when we cut the bar magnet, how we call this property?

Magnet is dipole, it means it has two poles

So for example when we cut bar magnet into two halves each half will have again its N pole and S pole

Describe magnet field

Magnetic field is the space around magnet where magnetic force acts

Define magnetic field lines and their properties

Magnetic field lines are imaginary lines which represent direction and strength of magnetic field

Prop:

-never cross

-form closed loops

-direction is from N to S pole

-the closer they are together the stronger the mag.field

What are kinds of magnetic field ?

1.stationary-the strength of the field does not change over the time

2.non-stationary-the strength changes over time

1.uniform-the strength of the field is the same at each point of m.f.

2.non-uniform-the strength is different at each point

What is conventional current direction?

From plus to minus

Magnetic field around conductor carrying current

If the conductor carries current it causes the deflection of the compass needle (magnet)

Bc. Around conductor carrying I there is magnetic field

Deflection of compass needle depends on:

1.magnitude of the current -I

2.distance between the conductor and the compass needle

Direction of the deflection depends on :

Direction of the current

Describe the right-hand rule

If the right hand claasps a conductor with the thumb pointing the direction of the current (conventional),then the fingers give the direction of the magnetic field lines

What type of magnetic field is between the poles on the horseshoe magnet

Uniform magnetic field

Magnitude of magnetic force on a conductor carrying current depends on:

Current -I-

Magnetic flux density -B-

Length of the conductor exposed to the magnetic field -L-

The position of the conductor in the magnetic field angle -alpha-

Describe Magnetic flux density

-vector physical quantity

-symbol: B

-unit: T tesla

Describes the strength of magnetic field

-formula: B=Fm/ILsinalpha

-direction of the vector of B is the same direction of the tangent line to the magnetic field line

Describe Fleming’s left hand rule

Fingers → I

Magnetic field lines enter the palm

Thumb →Fm