Electricity Flashcards
Electric charge?
Property of matter to attract or repel other materials. SI unit is coulomb (C)
Charge of electron?
1.6 x 10^-19 C
Q = n x e
Conductors?
Allow electrons to pass through them, has free mobile electrons in outermost shell.
Insulators?
Don’t allow current to pass through them. Don’t have free mobile electrons.
Semiconductors?
Allow some amount of electricity to pass through them.
Electric curent?
Rate of flow of electric charge. Unit is Ampere.
I = Q/T
Define ampere.
Flow of one coulomb of charge per second.
1A = 1C/1 second.
Ammetre?
Measure electric current in a circuit.
Potential difference?
Work done in moving a unit of positive electric charge from one point to another. (Measured with voltmeter.)
Electric potential?
Work done in moving a unit of positive electric charge from infinity to a certain point in an electric field. SI unit = Volt (V)
V = W/Q
Define one volt.
1 volt = 1 joule/1 coulomb
Electric circuit?
Continuous and closed path of electric current is called an electric circuit.
State ohms law.
At constant temperature, current flowing through circuit is directly proportional to potential difference applied across ends to conductor.
V = I x R
Resistance?
Property of a conductor to resist flow of charges through it. SI unit is ‘ohm’ Ω
1 Ω = 1 volt/1 ampere.
Variable resistance?
A component used to regulate current without changing the voltage source.