a type of lamp that uses a hot wire to emit light

a conductor for which the current is directly proportional to the p.d.

a relationship between variables in which one is a multiple of the other

a metal atom that has lost one or more outer electrons and has become positively charged

an electron from the outer shell of an atom that is free to move from ion to ion through a metal

Resistance of a hot metal

Physics

Measuring the resistance of a filament lamp

Measuring the resistance of a diode

Interpreting I–V graphs

Potential divider circuits

LDRs and thermistors

In the Mains electricity unit, they will build on this knowledge to learn about the dangers of mains electricity, how to use mains electricity safely, the equations I=Q/t, V=E/Q and P=IV, and about the transmission of power in the national grid, including transformers.

In the Electric fields and circuit calculations unit, pupils learnt about the properties of electric fields, moving electric charge, and how to analyse series and parallel electrical circuits.

This unit explores current, resistance, and potential difference. It covers circuit design for lamps, diodes, and thermistors, and emphasises planning experiments, data interpretation, and presenting scientific conclusions.

Circuit components

Which of the following components does the I–V graph shown represent?

Which of the following is an ohmic conductor?

an I–V graph for ohmic conductors is a curved line

an I–V graph for non–ohmic conductors is a straight line

an I–V graph for ohmic conductors is a straight line through the origin

the resistance of non–ohmic conductors is constant

Which of the following statements about ohmic conductors and non–ohmic conductors is correct?

In the model of a metal shown, what do the blue circles represent?

In the model of a metal shown, what do the black circles represent?

The electrons move as before and the metal ions vibrate more vigorously.

The electrons move more quickly and the metal ions vibrate less vigorously.

The electrons move more quickly and the metal ions vibrate as before.

The electrons move more quickly and the metal ions vibrate more vigorously.

What happens to the electrons and metal ions when a metal is heated?

Which of the following components is represented by the circuit symbol shown?

What happens to the current through a filament lamp as the p.d. across it is increased?

What is the resistance of a filament lamp if it has a current of 0.25 A when a p.d. of 0.5 V is applied across it?

Which of the following statements about the I–V graph of a filament lamp is correct?

it increases less quickly than when the p.d. across it is lower

it increases as the same rate as when the p.d. across it is lower

it increases more quickly than when the p.d. across it is lower

If the p.d. across a filament lamp increases at a steady rate, how does the current through it change as the p.d. becomes higher?

What is the resistance of the filament lamp at a p.d. of 3.0 V, according to the I–V graph shown?

Resistance of a hot metal

Lesson outcome