I live in the US and I heat my tea water in an electric kettle. It probably isn't as fast as yours, but it is still close to microwave speed. And I can heat up enough for several cups of tea and have it keep the rest hot. I usually drink more than one at a sitting.
Unless I'm misunderstanding your statement, you're saying it's faster to boil water in the microwave than the kettle? How's that possible? I would think the microwave has more wasted energy
I wonder what the efficiency of absorption is, though. Does 100% of emitted radiation get soaked up by the cup, or does some escape into the surroundings?
It doesn't get absorbed so much as excite the water particles as it passes through. I'd imagine it would be more effective in the beginning when they're standing relatively still.
My microwave can boil a single cup of water faster than my kettle. My kettle can boil four cups of water a lot faster than my microwave. It all depends on the microwave and kettle (and the voltage available).