Magnetic Materials Flashcards
Alternating current
Current flow consisting of charges that continually change direction. These oscillations usually occur at a set frequency.
Demagnetisation
Process of removing magnetic qualities in a material
Magnet
A magnet is a material or object that produces a magnetic field.
Bar magnet
Is a rectangular piece of an object that shows permanent magnetic properties
Direct current
Current flow consisting of charges flowing in a single direction only. Batteries and cells provide direct current.
Induced magnet
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.
Electromagnet
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.
Magnetisation
Process of inducing magnetic qualities in a material.
Magnetic materials
Iron, steel, cobalt and nickel.
Magnetic field
The region around a magnet in which another magnet or magnetic material will experience a force.
Magnetic field lines
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
Non-magnetic materials
Materials which are not attracted by a magnet.
Conductor
A material that allows electrical charge to flow easily. Metals are particularly good conductors due to the free electrons in their structures.
Permanent magnet
A magnet that produces its own magnetic field.
Coulomb(symbol: C)
The unit of charge.
Electric charge
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.
Electric field
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.
Electrostatic charge
The electric charge at rest on the surface of an insulated body.
Like charges
When two charges of the same polarity meet, they will repel.
Insulator
A material that doesn’t allow electrical charge to flow.
Point charge
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.
Unlike charges
When two charges of opposite polarities meet, they will attract.
Ammeter
A device connected in series with a component to measure the current that flows through it
Conventional current
Is defined as moving in the same direction as the
positive charge flow.
Electromotive force
The energy supplied by a source in driving charge round a complete circuit. Measured in Volts.
Electric Current
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.
Volt
The unit of potential difference (voltage). One volt is equal to one joule per coulomb.
Voltmeter
A device that is connected in parallel with a component to measure the potential difference (voltage) across it.
Ammeter
A device connected in series with a component to measure the current that flows through it.
Resistance
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
Circuit diagram
Is a graphical representation of an electrical circuit.
Parallel
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.
Conductor
A material that allows electrical charge to flow easily. Metals are particularly good conductors due to the free electrons in their structures.
Electromagnetic induction
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
Induced current
The current induced in a conducting loop that is exposed to a changing magnetic field
Magnetic field
The region around a magnet in which another magnet or magnetic material will experience a non-contact force.
