AQAGCSEPhysicsFoundation1 mark
GCSE revision question
Question context
A light bulb uses electrical energy measured in joules (J). Sometimes energy is given in kilojoules (kJ). The efficiency of the bulb depends on the useful light energy output compared to the electrical energy input.
Name the correct unit for energy used in efficiency calculations.
Show answer, mark scheme and Mentor explanation
Answer and mark-scheme guidance
MP1: joule (J)
Mentor — AI Tutor
Can you secure this 1-mark efficiency unit question?
This question is testing whether you can name the correct unit for energy used in efficiency calculations. The mark scheme awards the mark for joule (J). The context also signals that energy is measured in joules, while kilojoules may sometimes be used, so the exact wording that earns the mark is joule (J).
Quick takeaway: To get the mark, write joule (J).