CAIE IGCSE Physics Power Equations
Practise using P = W/t and P = ΔE/t, converting time units and combining power with gravitational, thermal or electrical energy relationships.
- Syllabus
- 2026–2028
- Course
- Physics 0625
Exam points
- substitute work done or energy transferred and time into P = W/t or P = ΔE/t
- convert minutes or hours before calculating in watts, joules, seconds or kilowatt-hours
- combine power with mgh, thermal energy or electrical data before solving the unknown
1.7.4.1—Power as work done per unit time or question 1
Fig. 3.1 shows a model of a wind turbine used to demonstrate the use of wind energy to generate electricity. The wind is blowing towards the model, as shown.
Fig. 3.1
The mass of air passing through the circular area swept out by the turbine blades each second is 7.5 kg . The kinetic energy of the air that passes through this circular area each second is 240 J .
The kinetic energy of the air drives a generator. State the input power of the air passing through the turbine blades.
input power =
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