Energy Fundamentals Check

1. The first law of thermodynamics states:

Energy is always lost as heatEnergy is conserved — it cannot be created or destroyed, only convertedHeat always flows from cold to hotEfficiency can approach 100% with perfect design

2. What is the relationship between energy and power?

They are the same thingEnergy = power × timePower = energy × timeEnergy is larger than power

3. Which unit conversion is correct?

1 kWh = 1 MJ1 kWh = 3.6 MJ1 kWh = 360 MJ1 MJ = 3.6 kWh

4. A 10 kW heater runs for 2 hours. How much energy does it use?

10 kWh20 kWh5 kWh2 kW

Knowledge check