P2 Flashcards
Series Circuit
One loop of wire
Parallel circuit
2 or more loops of wire
Current
The rate of flow of charge
Potential difference
The difference in amount of energy that charge carriers have between two points in a circuit
Resistance
A measure of How hard it is for the current to pass through a component in a circuit
Ohm’s law
The current through a resistor is DIRECTLY proportional to the potential difference provided that the temperature is constant
Ohmi conductor
An electric component where potential difference is directly proportional to current e.g. resistor
Non - ohmic conductor
An electric component that does NOT follow Ohm’s law - the current and potential difference are NOT directly proportional
What is the formula that links current, charge and time?
Q = I x T Q = Coulombs I = Amps T = Seconds
How does current behave in a series circuit
Current is the same throughout the series circuit
How does current behave in a parallel circuit
Current splits at junctions in a parallel circuit ; it is different in different loops
What is the formula that links potential difference, charge and energy?
E = Q x V E = Joules Q = Charge V = Potential Difference
What is the formula that links Energy, Power and time?
P = E/T P = Watts E = Joules T = Seconds
How do u convert KW into W
Multiply by 1000
How do u convert mA into Amps
Divide by 1000
Alternating current
In A.C, the current is constantly changing direction
Direct current
D.C only flows in one direction
National Grid
A network of transformers and cables that supply the UK with electricity
Step - Up Transformer
Increases the voltage in the cables which decreases the current. This also decreases the resistance so less heat is lost from the wires
Electric Field lines
Electric field lines flow away from the positive charges and towards the negative charges
What is the formula that links current, voltage and resistance? Include the units for each
V = I x R V = Volts I = Amps R = Ohms
How do u calculate resistance in a series circuit
Add up the resistance of all resistors in the circuit
What happens to the total resistance of two resistors in parallel
the total resistance of two resistors in parallel is less than the resistance of the smallest resistor
What happens to the resistance of a thermistor as it increases in temperature
The resistance decreases as the temperature increases
