How long does it take an iphone 3 to die completely?

[thatjusthappenede]

heres the story, I downloaded this app called cocoppa (stay away!) and it made my phone get this white screen. I try to shut it down but nothing happens. I suppose my only hope is to let it die. Unfortunately, I had charged my phone to a whopping 100% before this operation took place, so my question is, how long do i have to suffer being phoneless before my phone completely dies? the screen doesnt go dark at all, so i assume it shouldn't be that long as it uses more energy being bright.
life safer! Thank you )

 

[baseballmania342]

hold down the home button and the power button until you see the apple logo (up to 20 seconds).

 

[Matt]

I agree with the Apple logo method, however If you leave it at your desk side, it should take approximately 4-5 hours depending on how worn your battery is.