P7 - Fields Flashcards
What is back emf?
Emf generated by the coil in an AC generator which acts again the PD.
What is capacitance?
The charge stored per unit PD.
What is a capacitor?
An electrical component which stores charge.
What is a parallel-plate capacitor?
A capacitor made of two parallel conducting plates with an insulating layer called a dielectric in between.
What is 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.
What is a cyclotron?
A particle acceleration made of two dees, which uses an electric field to move from one electrode to another.
What is a dielectric?
An insulating layer between the plates in a capacitor to increase capacitance.
What is electric field strength?
The force per unit positive charge exerted on a charged object at that point in the field.
What kind of quantity is electric field strength?
Vector.
What is electric potential?
The work done per unit charge on a positive test charge in bringing in from infinity to that point in the field.
What is electromagnetic induction?
When emf is induced in a wire when it is moved relative to an electric field (cuts the field lines).
What are equipotential lines?
Lines along which you can move a particle with no work done.
What is escape velocity?
The minimum velocity required by an object to escape its gravitational field.
What is Faraday’s law?
The magnitude of induced emf is equal to the rate of change of flux linkage through the circuit.
What is a geostationary satellite?
A satellite that orbits above the equator with a 24hr period.
