2. Electricity Flashcards
What direction is ‘electron flow’ in?
Opposite direction of the conventional current
What is charge?
The electrons that are always in a wire - whether connected to a cell or not
What is current?
The flow of electrons in a conductor - when it’s connected to a cell in a complete circuit
What is current measured in?
Amps (A)
What is voltage?
The push and pull of electrons in a wire - makes electrons flow
What is voltage measured in?
Volts
What is electrical energy?
Energy carried by current and converted to heat and light energy
Is the current the same all the way round in series?
Yes
Why do electrical charges move through metals?
They have some electrons that are free to move from their atoms
What is an electric current?
A movement of charge
What is electrolysis?
When current flows in a liquid, carried by positive and negative ions
What happens when electrical current flows through a resistor?
Electrical energy is transformed into heat energy
What does the energy transferred depend on?
Amount of charge carried by electrons and p.d. Pushing the charge around
What charge do electrons have?
Negative
What is the unit for power?
Watt (W)
What happens to power as current increases?
Increases
What happens to a lamp when there is lower resistance?
the lamp is brighter
What do electrons have to do when passing through a wire?
Push their way through vibrating electrons
What does the resistance in a circuit do?
Limit the current
Ohms law?
The current through a resistor at a constant temperature is directly proportional to the potential difference across the resistor
What is the p.d. of cells?
The sum of the p.d. of each cell
In a series circuit…
- the same current passes through the components
- the p.d. of the voltage supply is shared between the components
- the total resistance of components is equal to the sum of the resistance of each component
In a parallel circuit…
- the total current through the whole circuit is the sum of the currents through the separate components
- the p.d. across each branch is the same
Is the voltage across each branch in parallel the same?
Yes