Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
Apple Release IOS 5.01 To Developers (Battery Life Fix) –
Apple has released iOS 5.0.1 developers.The update fixes a lot of things including battery issues which a lot of people have been complaining about, multitasking gestures (original iPad) , Improves quality of Voice recognition for Australian users , etc.
iOS 5.0.1 beta contains improvements and other bug fixes including:
– Fixes bugs affecting battery life
– Adds Multitasking Gestures for original iPad
– Resolves bugs with Documents in the Cloud
– Improves voice recognition for Australian users using dictation
– Contains security improvements
iOS 5.0.1 beta introduces a new way for developers to specify files that should remain on device, even in low storage situations.