Electricity Flashcards
What electric fields do particles that have a negative / positive charge have?
positive- outwards
negative- inwards
What is the difference between a current, voltage and electric charge.
Current is the flow of electrons a circuit has (Amos), whereas the electric charge is the rate of the current.
Voltage is the potential energy it would take to move electrons to a certain place from its starting position.
What factors can vary a wire’s resistance?
-length
-width
-material
-temperature
How can you relate electric charge, energy transferred and voltage?
voltage= energy transferred divided by coulombs.
What is a diode?
It allows the current to flow in one direction only.
What is a light-emitting diode?
It emits light when a current flows through it.
What is a resistor?
It changes (variable) the current or limits it (fixed).
What is resistance?
When electrons are opposed by atoms in a medium, effecting how easily they pass through.
What would happen to the current if the resistance was high/low? what conclusion can we draw from it?
If the resistance was high, the current would be low and vice versa. We can deduce that as resistance increases, current decreases.
If the current and the voltage of the wire are directly proportional, what does this tell us about the resistance?
The resistance is constant therefore the wire is an ohmic conductor.
What is static electricity?
When electrons that cause charges cannot move.
In AC terms, what does frequency refer to?
The number of cycles that the current takes in one second.
Describe how a thermistor’s resistance changes with temperature.
At a low temperature, the resistance is higher
What is the UK mains electricity’s average and max. voltage?
230V avg
325V max.
What is the UK mains frequency?
50Hz
