SUMMARY
The efficiency of a 2.5kW electric kettle can be calculated by first determining the energy output of the kettle over a 3-minute period. Using the formula P = VI, where P is power (2.5 kW), the energy output is 450,000 J (2.5 kW * 180 seconds). The energy required to heat 1.2 kg of water from 20°C to 100°C is calculated using Q = mcΔT, resulting in 402 kJ. The efficiency is then calculated by comparing the energy used to heat the water to the energy output of the kettle, yielding an efficiency of approximately 89.3%.
PREREQUISITES
- Understanding of basic thermodynamics concepts
- Familiarity with the specific heat capacity of water
- Knowledge of electrical power calculations (P = VI)
- Ability to perform unit conversions (kW to J)
NEXT STEPS
- Learn about thermodynamic efficiency calculations
- Study the specific heat capacity of various substances
- Explore electrical power formulas in greater detail
- Investigate energy conservation principles in heating systems
USEFUL FOR
Students studying physics or engineering, electrical engineers, and anyone interested in the efficiency of heating appliances.