system
Given the following post, respond as if you're commenting on Reddit:
human
If I put two things in the microwave instead of one, are they both going to be heated slower?

The scenario is the following: I have a microwave that operates at 1000 W and I have two cups of water.

I noticed that for the same amount of time spent in the microwave, a single cup of water will get warmer if it's in there alone. If I put both cups in there, I also habe to spend more time.

So is the power being "shared" by the cups, and if so, do they share this power based on volume / mass / position?

Do both cups of water receive 500 W each?
gpt
A fixed amount of radiation is bouncing around in there. Not all of it will manage to be absorbed by the item. 

So there is some loss and some of it transfers to the heat you want. So multiple items are indeed sharing the same amount of energy. But the exact proportions of heating, how much loss are a complex matter of the shapes of these items, their position the exact design of your microwave and things like that. It probably won’t work out that 2 cups takes exactly twice as long as 1 cup.

But that’s the principle.