Linking current, potential difference and resistance

Physics

Electric fields

Moving electric charge

Resistance of a wire at a constant temperature

Analysing series circuits

Adding components to a parallel circuit

Analysing parallel circuits

In the Circuit components unit, they will build on this knowledge to learn how the resistance of filament lamps and diodes change with current and about the properties and applications of light dependent resistors and thermistors.

In the Resistance and parallel circuits unit, pupils learnt about electrical resistance and parallel electric circuits.

This unit covers static electricity, electric fields, and current flow in series and parallel circuits. It explains current, resistance, and potential difference relationships and explores diodes, thermistors, and LDRs. The focus is on calculations, experiments, and accurate measurements.

Electric fields and circuit calculations

a measure of how difficult it is for charge to move around a circuit

the amount of charge passing a point in one second

a measure of the ‘push’ on electrons in a circuit

Match the following quantities to its definition.

The potential difference of the cell decreases.

A series circuit contains only a cell and a lamp. Which of the following changes occurs if another lamp is added, in series with the first lamp?

In a series circuit, there is a particular type of relationship between current and total resistance: the current is {{}} proportional to the total resistance, if the p.d. stays the same.

The potential difference across a 10 Ω resistor in a circuit is 4.0 V. What is the current in the resistor?

A motor has a resistance of 6.0 Ω. What p.d. is needed to make a current of 1.5 A flow through the motor?

A pupil has identical lamps and identical cells. He connects two cells and two lamps in series. Then he changes the circuit, but the current does not change. Which of the following could he have done?

The number of coulombs that flow past a point each second equals the…

A circuit which has only one loop is called a {{}} circuit.

In a circuit, electrons flow through the wires away from the {{}} end of the battery.

There is an electric field around the battery only.

There is an electric field around the whole circuit.

Electrons nearest the battery experience the most force.

Electrons experience the same force in all parts of the circuit.

In a circuit with a single loop, which of the following statements are correct?

The equation relating current, charge and time is: current = charge ÷ time. Which of the following equations is the correct rearrngement of the equation with time as the subject?

Linking current, potential difference and resistance

Lesson outcome