Topic 9 - Electricty & Circuits and Static Electricity Flashcards
voltage/potential difference
the pressure used to push the free electrons around the circuits
-> amount of potential energy the cell transfers to each coulomb of charge flowing through it
which way does the conventional current direction go
goes from the positive terminal to the negative terminal of the battery
series circuit
only one route
parallel circuit
circuit that contains different junctions (branches) for the current take different routes
unit for electric current
amps (A)
ammeter
measures the current passing through a component or circuit
what is a source of potential difference
cell or battery
what happens to the current if the potential difference is increased
the current increases
unit for potential difference
volts
voltmeter
measures the voltage
where is a voltmeter connected?
a voltmeter is always connected in parallel to measure the potential difference across the component or circuit
what is the unit for electric charge
coulombs (C)
current
rate a which electrons flow past a point in an electrical circuit
what is the current in a metal
flow of electrons
What size of the current at any point tell you about the charge?
tells you how much charge flows past that point each second
electrical current
The rate of flow of charge
charge equation
charge = current x time
potential energy
The energy stored in the circuits electrons due to their position in the electric field
how do you get energy to a circuit
The cell transfers energy to the charge so the charge then has a potential to transfer energy to other components in the circuit
Energy transferred equations
- Energy transferred = charge moved x potential difference
- Energy transferred = current x potential difference x time
units for resistance
ohms
potential difference equation
Potential difference = current x resistance
Why is there a greater potential difference across some resistors but not others?
because resistors with higher resistance have greater potential difference
what happens in a parallel circuit when resistors are added?
The total resistance of the circuit is less than the resistance of the individual resistors because there are now more paths for the current