Question

If a kettle uses 0.25 kW and you run the kettle every morning for 10 minutes. How much energy are you using in a week?

Answer 1

Energy is power multiplied by time. 10 minutes (600 seconds) 7 days a week is 7*600=4200 s of kettle operation. Multiplied by its power, it gives us the energy of

$$E=Pt=0.25·4200=1050\text{ kJ} .$$