Can US Power Adapter be used in Europe?

They are electrically compatible but you'll need to determine if you need a mechanical adapter so that the plug fits properly in the receptacle.

You will definitely need a power converter with the proper type of plug for Europe. They are very inexpensive and are available at most electronic stores.

If talking of the 10watt charger that came with your iPad and has a removable plug - it'l work with just a simple plug adapter.

I just returned from Spain, you can definitely use your US power cord but you will need a plug adapter....not a power converter. The plug adapter allows you to use their sockets with the north american plugs, whereas a power converter changes the voltage from 220 ( used throughout Europe) to 110 (used in NA). Most electronics sold now have built in converters....you can check this by checking the warning label on your equipment...if it shows a range of power from 110- 220 then you don't need to use a converter.

Yes you can use the charger in Europe...rated for 100-240 volts and 50-60 Hertz. As the others have said, all you need is either a pin adapter or replacement pin piece. The pin piece slides off horizontally. Apple sells a world traveler kit that has replacement pin pieces for most countries. You may be able to convince an Apple store in Italy to sell you just the pine piece for Continental Europe...France, Italy, Germany, etc., all use the same pin configuration.

You can also buy the US to Europe pin converter in many airports in Europe.

And your hotel may well have one if you forget--you'd be surprised how many people leave them behind, so most hotels have a drawerful, although it's safest to come prepared.

I just returned from Italy and can definitely say that the power adapter didn't work, even when it fit the receptacle. Luck I brought a 30 year old power adapter that still works.

Your experience flies in the face of everything that the electronics and the electrical industries have accomplished over the last fifty years. Most likely the plug didn't truly fit properly. Just because it went in to the receptacle doesn't mean that it made electrical contact.