7. Fields And Their Consequences Definitions Flashcards
Define back EMF
An emf generated by the coil in an AC generator that acts against the potential difference that has been supplied to the motor
Define capacitance, C
The charge stored per unit pd in a capacitor
Define capacitor
An electrical component that stores charge. A parallel-plate capacitor is made of two parallel conducting plates with an insulator between them (dielectric)
Define Coulomb’s law
The size of the force that acts between two point charges is proportional to the product of their charges and inversely proportional to the square of their separation. It is attractive for opposite charges and repulsive for like charges.
Define cyclotron
A particle accelerator made up of two D shaped electrodes positioned opposite each other. The electric field changes direction each time a particle moves from one electrode to the other, causing the particle to accelerate
Define dielectric
An insulating material placed between the two plates of a capacitor in order to increase the amount of charge it can store
Define electrical conductor
A material that contains free electrons that are able to move throughout the material and carry charge
Define electrical insulator
A material that does not contain any free electrons. All electrons in an insulator are part of the individual atoms that make it up.
Define electric field
A region surrounding a charged object which causes a force to be exerted on any charged object placed within the field
Define electric field strength ,E (at a point in the field)
The force per unit positive charge exerted on a charged object placed at that point in the field. This is a vector acting in the same direction as the force on a positive charge.
Define electric potential, V (at a point in the field)
The work done per unit charge in a positive test charge in bringing it from infinity to that point in the field.
Define electromagnetic induction
When an emf in induced in a wire/conducting rod when it is moved relative to a magnetic field.
Define equipotential
A surface of constant potential. No work is done by the field when an object moves along an equipotential
Define escape velocity
The minimum velocity required by an object to be able to escape a gravitational field of a mass when projected vertically from its surface.
Define Faraday’s law
The magnitude of the induced emf is equal to the rate of change of flux linkage through the circuit