Non-stop backup technical questions

Recently purchased Acronis TrueImage 2014 for my wife's laptop. I currently have it setup to backup to an external drive, but have some technical questions that wasn't answered by FAQ and couldn't be found online.

1. What happens if you disconnect the external hard drive? Ideally, you should stop NSB, then eject the external drive and then disconnect the drive. In real life, my wife is unlikely to remember to do that and just disconnect the drive. How does TrueImage handle this? Will it just restart the last partial backup?

2. Judging from the files, Trueimage does a full backup and then a bunch of partial backup. Is this backup a differential or incremental. Basically if version 3 backup of a file is corrupted, will this also corrupt later version (like version 5) of the backup?

3. Can Trueimage detect the drive being reconnected as a different drive letter? What I don't want to unplug drive E:, then reconnect another external drive and have Trueimage start backing up to that external drive. I assume they add some sort of file to the external drive so that it knows when it will be reconnected as a different drive letter?

Paul