Energy and Potential Difference in Circuits Flashcards
Define electric current
Is the rate of flow of charge
In a wire, which direction do the electrons flow
Negative to positive
What is convectional current
Flowing around the circuit from the positive to negative terminal.
What does current mean
flowing from positive to negative per second
What is charge measured in
Coulombs, (C)
What is current measured in
Amps (A)
In the equation “charge, current, time” What does Q and I stand for in the triangle
Q = Charge I = Current
Give the equation to find out the charge from the current and time
Charge = Current x Time
What is time always measured in
Seconds
What charge passes if 4A flows for 20 seconds
CHARGE = CURRENT X TIME Current = 4 Time = 20 4 x 20 = 80 Charge = 80C
What is the difference between a parallel and Series circuit
Parallel splits
Series is a continues line.
What does an Ammeter measure
Current
Why do you start the variable resistor to maximum at the start of the experiment
So that the equipment doesn’t break straight away.
The….current in a parallel circuit is equal to the sum of the currents in the …….sections of the circuit
Total
Parallel
What is used to measure volts
A voltmeter
In series, current is……everywhere
Equal
In parallel, Total current =………..
Amp 1 + Amp 2 + Amp 3
Define resistance
The ratio of the voltage, to the current
Give the equation that links voltage, current and resistance
Voltage = Current x resistance
What is resistance measured in
Ohms, (Ω)
Calculate the voltage required to cause a current of 3A to flow through a resistance of 5 Ω
Current = 3
Resistance = 5
3 x 5 = 15
Voltage = 15V
What does m and k mean
M = ÷ 1000 K = x 1000
When a……flows through a component that has………, the component….up and it’s…….increases
Current
Resistance
Heats
Temperature
Describe the shape of the graph for the resistance in a wire
Resistance is constant
Line is perpendicular
Describe the shape of the graph for the resistance in a bulb
The line goes perpendicular up to a point, but then levels off. The resistance increases due to heat.
Describe the shape of the graph for the resistance in a diode
The line remains very low and flat before suddenly shooting upward almost vertically.
As the length of wire……………the more the resistance…… up to point where the resistance……………………..
Increases
Increases
Levels off
What do LED’s do
They emit light when a current flows through them.
What does power mean
Measures the rate at which electrical energy is transferred, (usually turned into heat)
What is power measured in
Watts (W)
Give the equation that links power, work done (energy) and time
Work done = Power x Time
What is work done measured in
Joules
Give the equation that links power, current and voltage
Power = Current x Voltage
