Efficiency (Edexcel GCSE Physics Combined Science): Flashcards

Measure of how well a device converts input energy into useful energy

Wastes little energy

Wastes most of input energy

Thermal energy stores in surroundings

$\frac{\text{Useful energy}}{\text{Total energy}} \times 100$

Joules (J)

Less than 100%

Energy cannot be created (conservation law)

Reduces friction between moving parts

Reduces thermal energy dissipation to surroundings

Wasted heat

$\text{Total Energy} = \text{Useful Output} + \text{Wasted Energy}$

Reduce air resistance

Heat in surroundings