Different processes have different efficiencies.
Which row in the table below shows the most efficient process?
| Energy input / J\text{J}J | Useful energy output / J\text{J}J | |
|---|---|---|
| A | 50 | 12 |
| B | 200 | 60 |
| C | 120 | 30 |
| D | 500 | 110 |
A
B
C
D
533 exam-style questions on CIE IGCSE Physics 1.7 Energy, work and power, covering 1.7.1a Energy stores and energy transfers, 1.7.1b Conservation of energy, 1.7.1c Kinetic and gravitational potential energy, 1.7.2 Work done, 1.7.3 Energy resources, 1.7.3a Energy resources and electricity generation, 1.7.3b Nuclear fusion as an energy source, 1.7.3c Efficiency of energy transfer, and 1.7.4 Power. Each one has a worked solution and a mark scheme showing where the marks go.