You don't use batteries in microwaves.
About the size of a microwave
It crackles and pops. You would probably have to get a new microwave if you attempted this at home.
nothing would happen the microwave does not know if there is anything in there or not.
Nothing
they get recycle
There are no dangers of putting a baby's bottle in the microwave.
If you microwave nothing, the microwave will not heat up anything and there will be no change in temperature or appearance. The microwave will simply run without any effect on the empty space inside.
it might explode
It explodes.
The human will be cooked from the inside out.
nothing good