4. Capacitors Flashcards
Capacitance, C:
The charge stored per unit pd in a capacitor.
Capacitor:
An electrical component that stores charge. A parallel-plate capacitor is made of two parallel conducting plates with a dielectric (insulator) between them.
Dielectric:
An insulating material placed between the two plates of a capacitor in order to increase the amount of charge it can store.
Faraday’s Law:
The magnitude of the induced emf is equal to the rate of change of flux linkage through the circuit.
Polarising in terms of cappacitors and electric fields
An atom becomes polarised when an external electric field causes the negative electron cloud to be shifted in the opposite direction to the positive nucleus
the charges are pulled in opposite directions.
Step-down Transformer:
A device made of two insulated wires coiled around an iron core in which the output voltage is smaller than the input voltage due to the secondary coil having fewer turns than the primary coil
What is Lenz’s law?
the direction of the induced emf is such that it will try to opposes the change that is producing it.
The capacitance of a capacitor is affected by….
The area of the plates,
the distance between the plates,
the ability of the dielectric to support electrostatic forces.
What is meant by a dielectric constant 6.0?
How does a dielectric work?
(Electric field exists between plates)
Polar molecules align with their positive side facing the negative plate (owtte) v1
producing a counter electric field/reducing the field between the plates v2
The pd V reduces between the capacitor plates but charge O remains the same so capacitance O/V increases.
Define tesla
The force exerted on a 1m length of current-carrying wire that is perependicular to the magnetic field
