Series & Parallel Circuits Practice Questions

State the frequency and the potential difference of the UK domestic mains electricity supply.

Explain the difference between an alternating potential difference and a direct potential difference.

Complete the table below.

The neutral wire completes the circuit. State the function of the earth wire.

A student says, 'The earth wire carries a current whenever the kettle is switched on.'

Explain why the student is wrong.

Which circuit has two resistors connected in parallel with each other?

Circuit ____

Which circuit contains both a series part and a parallel part?

Circuit ____

In circuit A the two resistors have resistances of $15\ \Omega$ and $25\ \Omega$.

Calculate the total resistance of circuit A.

Determine the reading on ammeter A3.

State the potential difference across lamp L2.

Give one advantage of connecting the two lamps in parallel rather than in series.

Calculate the resistance of lamp L1.

Use the equation:

$\text{resistance} = \dfrac{\text{potential difference}}{\text{current}}$

State the current through lamp L2.

Calculate the potential difference across lamp L2.

Calculate the resistance of lamp L1.

A third identical lamp is now added to the circuit, in series with L1 and L2.

Explain the effect this has on the brightness of lamp L1.

Calculate the total resistance of the circuit.

Determine the resistance of resistor R.

Calculate the potential difference across the $30\ \Omega$ resistor.

A second $15\ \Omega$ resistor is now connected in series in the same circuit.

Calculate the new ammeter reading.

Describe how the ammeter and the voltmeter should be connected in the circuit.

Explain why the technician includes the variable resistor in series in the circuit.

Describe two differences between a series circuit and a parallel circuit.

Explain why the total resistance of the two elements connected in series is greater than the resistance of one element on its own.

Explain why the total resistance of the two elements connected in parallel is less than the resistance of one element on its own.

State which arrangement, series or parallel, gives the larger current through the supply.

Calculate value X in the table.

$X = \_\_\_\_\ \Omega$

State the resolution of the ohmmeter used by the student.

The student concluded that the total resistance is directly proportional to the number of resistors connected in series.

Explain why the student was correct. Use data from the table in your answer.

The switch on the hedge trimmer is open, but the plug is still in the socket.

Explain why the live wire inside the hedge trimmer is still dangerous.

Explain why providing any connection between the live wire and earth is dangerous.

The metal case of the hedge trimmer is connected to the earth wire.

Explain how this reduces the risk of an electric shock if the live wire becomes loose and touches the metal case.

State how resistor R2 and resistor R3 are connected to each other.

Calculate the potential difference across R1.

Determine the potential difference across R2.

Calculate the current through R2.

Calculate the resistance of R3.