p2 - Electricy Flashcards
State an equation that links current ,charge flow and time. write the units for each.
Charge flow (C) = Curent (A) * Time (s)
What is the equation that links potential difference , current and resistance ?
potential difference = current / resistance
What is an I-V characteristic.
A graph showing how the current flowing through a component changes as the potential difference across changes.
What happens to the resistance of a thermistor as it gets hotter?
resistance drops.
True or false ? potential difference is shared between components in a series circuit.
True
How does the overall resistance of a circuit change when a resistor is added in parallel?
Reduces the total resistance
What is the potential difference and frequency of the UK mains supply ?
230 V frequency - 50 Hz (hertz)
Name and give the colors of the three wires in a three core cable.
Live wire - Brown
Earth wire - Yellow and green
Neutral wire - blue
Describe the useful energy transfer that occurs for a battery powered fan.
Energy is transferred electrically from the battery to the kinetic energy store.
State three equations that can be used to calculate electrical power.
Energy transferred = power * time
Energy transferred = charge flow / potential difference
Power = current *2 / resistance
how are the step - up and step - down transformers used in the national grid?
Step - up : to increase the potential difference from power stations to electric cables.
Step - down: brings the potential difference back down to a safe level before entering the home.
