Physics, Heat Transfer Fluid, Atmospheric Physics.
1200 W microwave on high for about 2 minutes and it came to a boil. Let’s go to the whiteboard: In 6 hours (== 21,600 seconds) I used some fraction of that 100-W (the IR portion). Let’s call it 30%. How much energy have I expended? The power is a measure of energy/time. 1 Watt == 1 Joule/sec, so