Magnetic Materials

Question 1

Alternating current

Answer 1

Current flow consisting of charges that continually change direction. These oscillations usually occur at a set frequency.

Question 2

Demagnetisation

Answer 2

Process of removing magnetic qualities in a material

Question 2

Magnet

Answer 2

A magnet is a material or object that produces a magnetic field.

Question 2

Bar magnet

Answer 2

Is a rectangular piece of an object that shows permanent magnetic properties

Question 3

Direct current

Answer 3

Current flow consisting of charges flowing in a single direction only. Batteries and cells provide direct current.

Question 4

Induced magnet

Answer 4

A material that becomes a magnet when it is placed in an existing magnetic field, but loses its magnetism quickly once it is removed. Induced magnetism always produces attractive forces.

Question 5

Electromagnet

Answer 5

A solenoid with an iron core. The magnetism of an electromagnet can be switched on and off, and the strength changed, through varying the current in the solenoid.

Question 6

Magnetisation

Answer 6

Process of inducing magnetic qualities in a material.

Question 7

Magnetic materials

Answer 7

Iron, steel, cobalt and nickel.

Question 7

Magnetic field

Answer 7

The region around a magnet in which another magnet or magnetic material will experience a force.

Question 7

Magnetic field lines

Answer 7

Lines that show the strength and direction of a magnetic field. The lines point from North to South and their concentration represents the magnitude of the field

Question 8

Non-magnetic materials

Answer 8

Materials which are not attracted by a magnet.

Question 9

Conductor

Answer 9

A material that allows electrical charge to flow easily. Metals are particularly good conductors due to the free electrons in their structures.

Question 10

Permanent magnet

Answer 10

A magnet that produces its own magnetic field.

Question 11

Coulomb(symbol: C)

Answer 11

The unit of charge.

Question 12

Electric charge

Answer 12

Is the physical property of matter that causes it to experience a force when placed in an electromagnetic field. There are two types of electric charges: positive and negative.

Question 13

Electric field

Answer 13

A region in which a charge will experience a non-contact, electric force. All charged objects have an electric field around them, and this field is stronger the closer you are to the charge.

Question 14

Electrostatic charge

Answer 14

The electric charge at rest on the surface of an insulated body.

Question 14

Like charges

Answer 14

When two charges of the same polarity meet, they will repel.

Question 15

Insulator

Answer 15

A material that doesn’t allow electrical charge to flow.

Question 16

Point charge

Answer 16

The electric field around a point charge becomes weaker the further away you are. The field lines for a positive charge point radially outwards, whereas the field lines for a negative charge point radially inwards.

Question 17

Unlike charges

Answer 17

When two charges of opposite polarities meet, they will attract.

Question 18

Ammeter

Answer 18

A device connected in series with a component to measure the current that flows through it

Question 19

Conventional current

Answer 19

Is defined as moving in the same direction as the
positive charge flow.

Question 20

Electromotive force

Answer 20

The energy supplied by a source in driving charge round a complete circuit. Measured in Volts.

Question 21

Electric Current

Answer 21

The rate of flow of electrical charge. Its value is the same at any position in a single closed loop. In metals, the charges that flow are electrons.

Question 22

Volt

Answer 22

The unit of potential difference (voltage). One volt is equal to one joule per coulomb.

Question 23

Voltmeter

Answer 23

A device that is connected in parallel with a component to measure the potential difference (voltage) across it.

Question 24

Ammeter

Answer 24

A device connected in series with a component to measure the current that flows through it.

Question 25

Resistance

Answer 25

A measure of the opposition to current flow. Calculated as the ratio of the p.d. applied to the electric current which flows through it

Question 26

Circuit diagram

Answer 26

Is a graphical representation of an electrical circuit.

Question 27

Parallel

Answer 27

Components connected in parallel have the same potential difference across each component. The current from the source is larger than the current in each branch and the total current is equal to the sum of the currents flowing through each component.

Question 28

Conductor

Answer 28

A material that allows electrical charge to flow easily. Metals are particularly good conductors due to the free electrons in their structures.

Question 29

Electromagnetic induction

Answer 29

Is the production of an electromotive force across an electrical conductor in a changing magnetic field. The direction of an induced e.m.f. opposes the change causing it

Question 30

Induced current

Answer 30

The current induced in a conducting loop that is exposed to a changing magnetic field

Question 31

Magnetic field

Answer 31

The region around a magnet in which another magnet or magnetic material will experience a non-contact force.