P2 Series Circuits (page 183) Flashcards
What are Series Circuits?
its All or Nothing
What happens in a series circuit?
the different components are connected in a line, end to end, and between the +ve and -ve of the power supply (expect for voltmeters, where are always connected in parallel, but they don’t count as part of the circut).
What happens in a Series Circuit if you remove or disconnect one component?
the circuit is broken and they all stop. (this is generally not very handy, and in practice very few things are connected in series.
(see diagram 1 on page 183).
What rules do you follow to design a series circuit to measure quantities and test components?
Potential difference is Shared.
In series circuit the total pd of the supply is shared between the various components. So the potential differences round a series circuit always add up to equal the source pd:
V total = V1 + V2 + …
In series circuits the Same Current flows through what?
flows through all components,
i.e
I1 = I2 = …
(current is the same everwhere)
In series circuits the total reisitance of two components means what?
means its just the sum of their resistances:
R total = R1 + R2
This is because by adding a resistor in series, the two resistors have to share to the total pd.
The potential difference across each resistor is lower or higher, explain your answer?
the resistor is lower, so the current through each resistor is also lower. In a series circuit, the curent is the same everywhere so the total current in the circuit is reduced when a resistor is added. This means the total resistance of the circuit increases.
The bigger the component’s resistance, means what?
the bigger its share of the total potential difference.
Look at diagram near bottom of page 183.
Calculate the current passing through the circuit?
1) First find the total resistance by adding together the resistance of the two resistors.
2) Then rearrange V = IR and substitute in the values you have.
R total = 2 + 3 = 5 Ω
I = V ÷ R
= 20÷ 5
= 4 A
There is a bigger pd when more cells are in series, if they’re all connected the same way. give example?
when two cells with a potential difference of 1.5 V are connected in series they suppy 3 V between them.
(cell potential differences add up).
A battery is connected in series with a 4 Ω resistor and a 6 Ω resistor. A current of 0.6 A flows through the circuit. Calculate the potential difference of the battery. (3 marks).
R total = 4 + 5 + 6 = 15 Ω (1 mark)
V = I x R = 0.6 x 15 (1 mark) = 9 V (1 mark)
