Magnetism

Question 1

0What are field lines?

Answer 1

Lines of force that exist around a magnet

Question 2

What does current in a wire cause?

Answer 2

A magnetic field outside of the wire

Question 3

What are two things that causes a current to flow in wire

Answer 3

Moving a coil of wire near a magnet
Moving a magnet near coil of wire

Question 4

Define magnetism
Sir definition

Answer 4

Magnetism is a physical property, exhibited by some materials due to the presence of a magnetic force field radiated by the material.

Question 5

Define magnetism
Google definition

Answer 5

The force that attracts or repels an object which has metal to towards it or away from the magnet

Question 6

Define magnetic field

Answer 6

The region which surrounds a magnet and where the magnetic force can be felt

Question 7

What is the cause of all magnetism?

Answer 7

Current

Question 8

Define electromagnetism

Answer 8

Magnetism caused by a current running through a wire

Question 9

What are ferromagnetic materials?

Answer 9

Materials that are attracted by magnets

Question 10

How does ferromagnetic materials create magnetism?

Answer 10

The magnetic materials that have unpaired electrons an their atoms lineup near each other so that unpaired electrons spin in the same direction, spinning causes magnetism

Question 11

What are the properties of lines of magnetic flux?

Answer 11

They do not cross or intersect each other
The closer lines are to each other, the stronger the magnetic field

Question 12

define magnetic flux

Answer 12

The lines that represent the magnetic field

Question 13

what is magnetic flux denoted by

Answer 13

Φ

Question 14

what is the unit of magnetic flux Φ

Answer 14

Weber Wb

Question 15

Define magnetic flux density

Answer 15

The amount of magnetic flux Φ passing through per unit area of space
and which is perpendicular to the magnetic flux

Question 16

Magnetic flux density or the magnetic field strength is denoted by

Answer 16

B

Question 17

The unit of magnetic field strength is the

Answer 17

Tesla [T]

Question 18

When is the magnetic flux through a wire at its maximum value

Answer 18

when to field lines are perpendicular to the plane of the loop

Question 19

When is the magnetic flux through a wire at 0

Answer 19

when the field lines are parallel to the plane and don not cross the plane

Question 20

Magnetic flux density aka magnetic field strength formula

Answer 20

B =Φ/A

Question 21

What does x indicate

Answer 21

into the page

Question 22

what does • or ● indicate

Answer 22

out of the page (roll out)

Question 23

What rule can be used to determine the the direction of current and lines of magnetic flux

Answer 23

the right hang grip rule
your thumb faces the direction of thumb faces the direction of current and your fingers face the direction of the lines of magnetic flux.

Question 24

What direction do the lines of magnetic flux point

Answer 24

The direction of flow

Question 25

What is the magnetic field represented by

Answer 25

Lines of magnetic flux

Question 26

What is another name for magnetic flux density

Answer 26

Magnetic field strength

Question 27

Lines of magnetic flux orginate

Answer 27

From the north Pole and terminate onto a south pole

Question 28

What does the arrow —> represent

Answer 28

In the plane of the page

Question 29

When the current is flowing into the page, what direction is the field flowing

Answer 29

Clockwise direction

Question 30

When the current is flowing out of the page , what direction is the field flowing in

Answer 30

Anticlockwise

Question 31

The right-hand screw rule is used to

Answer 31

Determine the direction of the lines of magnetic flux

Question 32

What causes the forced to be exerted on a current-carrying conductor, placed in a magnetic field

Answer 32

The 2 magnetic fields interacting with each other.That is the magnetic field from the current carrying conductor, and whatever is producing the magnetic field example a magnet

Question 33

The magnetic force exerted on the current carrying conductor, placed in a magnetic field, depends on

Answer 33

The magnetic field strength/ magnetic flux density Strength of electric current Length of conductor perpendicular to magnetic field The direction of the magnetic field

Question 34

What equation expresses the relationship between the force magnetic field strength and electric current

Answer 34

F= BILsinθ Where F is the force acting on the conductor B is the magnetic flux density in T I is the current in A L is the length of the conductor in m θ is the angle between the magnetic field and conductor

Question 35

When is an emf produce in a conductor

Answer 35

When the current carrying conductor moves through the magnetic field such that it cuts through the lines of magnetic flux

Question 36

It the conductor forms apart of a circuit what will the emf generated do (aka electromagnetic induction)

Answer 36

It will cause a electric current to be induced within the conductor as a result of cutting the lines of magnetic flux

Question 37

What does emf stand for

Answer 37

Electromotive force

Question 38

What are the laws of electromagnetic induction

Answer 38

Faraday’s law and Lenz’s law

Question 39

Define inductance

Answer 39

Is a property of an electrical circuit where an emf is induced in a conductor due to the change of magnetic flux, cutting the conductor due to a change in current.

Question 40

When does Self inductance occur

Answer 40

When an emf occurs within the same circuit which has the changing current

Question 41

What is the unit of inductance

Answer 41

Henry H

Question 42

What is a transformer

Answer 42

A device that uses the phenomenon of mutual inductance to change the values of alternative voltages and currents

Question 43

What is a step up transformer

Answer 43

A transformer where the voltage on the second bidding (output) is greater than the primary winding voltage (input)

Question 44

What is a step down transformer

Answer 44

A transformer where the voltage on the secondary winding (output) is less than the voltage on the primary winding (input)

Question 45

What does the transformer ratio state

Answer 45

the ratio of the secondary to primary voltages in a transformer is equal to the ratio of the number of loops in their coils

Question 46

Give the transformer ratio

Answer 46

Np/Ns=Vp/Vs =Is/Ip

Question 47

What is an ideal transformer

Answer 47

A transformer with no power loss

Question 48

What is the turn ratio

Answer 48

Np/ Ns Number of turns in the primary winding / Number of turns in the secondary winding