CP9: Electricity and Circuits Flashcards
(32 cards)
What is voltage also known as?
Potential difference
How does the p.d. vary when connected in series and parallel?
Series- total p.d. shared between each component
Parallel- same p.d. across each component
Where must a voltmeter be placed in a circuit?
In parallel with the component that is being measured.
State the equation relating p.d. with energy transferred and charge
P.d. = energy transferred /charge
V=E/Q
What is current measured in?
Amps
What is voltage/p.d. measured in?
Volts
What is charge measured in?
Coulombs
What is an electric current?
The rate of flow of charge.
State the equation linking charge, current and time.
Q= I x T Charge= current x time
What two factors does the current in a circuit depend on?
P.d. and resistance
State the equation linking p.d., current and resistance.
V= I x R P.d.= current x resistance
What is an ammeter?
A component that measures current.
What happens when current reaches a junction in the circuit?
Current is conserved. Total current remains the same and is split between two branches.
In a closed circuit, if there was a p.d. there would also be a…
Current
How is current defined?
Rate of flow of charge
How does resistance affect current in a circuit?
As the total resistance of a circuit increases, the current flowing through the circuit decreases.
Give an example of when a thermistor might be used
In a thermostat to turn a heater on below a certain temperature.
What factors affect the energy transferred when charge flows through a component?
Amount of charge and the p.d. across the component.
State the equation linking energy, current and p.d.
E= V x I x T Energy= p.d. x current x time
Define p.d. in terms of charge
The work done per unit charge
State the equation linking p.d. and charge
E= Q x V
Energy transferred= charge x p.d.
Define power
The rate of energy transfer or the rate at which work is done.
Units of power?
Watts, W
State the equation linking power, p.d. and current
P= I x V Power= current x p.d.
