Many filament lamps in homes have been replaced by LED lamps that give out the same amount of light.
Why is an LED lamp more efficient than a filament lamp?
It transfers more energy each second for the same light output
It stores energy in its chemical store until the light is needed
It transfers less energy to thermal stores for the same light output
It has a higher power rating, so more light energy is emitted
50 exam-style questions on OCR GCSE Physics 7.2 Power and efficiency, covering 7.2.1 Dissipation of energy, 7.2.2 Energy transfers in domestic devices, 7.2.3 Power ratings of domestic appliances, 7.2.4 Efficiency of energy transfers, 7.2.5 Ways to increase efficiency, 7.2.6 Reducing unwanted energy transfers, and 7.2.7 Thermal conductivity and the cooling of buildings. Each one has a worked solution and a mark scheme showing where the marks go.