Investigating the efficiency of a light bulb: results

The graph below shows the plot of the voltage input against the temperature and light produced from the bulb.

Graph of Temperature, Light Intensity and Voltage against time

Teachers’ notes

Safety issues

Care should be taken to avoid touching the bulb whilst it is hot.

Target age groups

Ages 14 - 19 (Science Key Stage levels 4 and 5).

National curriculum

Whilst to some extent this can relate to GCSE level, the calculations involved require some knowledge of Specific Heat Capacity and Heat Capacity so may well be better placed post-16. The activity involves the use of a 12 W bulb placed inside a box and the voltage applied to the bulb, the temperature of the box and the light level all being measured. KS4 Sc4 Physical processes. Energy resources and energy transfer. Energy transfer. 5b about the efficient use of energy, the need for economical use of energy resources, and the environmental implications of generating energy.