only the iMac and the mac Pro
both
get a step down transformer whose output is equal to the voltage of your bulb
no
yes
i am quite sure these adapters have a "resister"of sorts (voltage regulator) in them which holds back any voltage above say 100v. So they are still runnig internaly at 100v even when plugged into 240v outlet
PL is mean Plug in - Light Bulb, the most comment application is CFL (Compact Fluorescent Lamp) which require assistance components to make it work or light it up, different to incandescent light bulb, it can light up by just itself direct connect to our home electricity ac 100v to ac 240v.
There will be no problems as the Mac laptops are designed to work internationally with a line voltage ranging from 100V to 240V.
Do you mean a 220V as in a power in Europe? Then,Check your adaptor. It will tell you the input voltage. If it sates that the range of the input voltage in 100V-240V then YES you can plug in your adapter into a 220V outlet.Please note that some people advise that you plug in the adapter into the power before plugging it into the computer.
as much as your mum eats grapes
Yes.
Its on the specifications of the device you will plug