Is it possible to receive an email immediately after one of my questions is answered?
No. You can select to receive emails daily by checkmarking the box at the bottom of your questions, but there is no option for immediate emails. However, if you stay on a Stack Exchange site, the inbox in the upper left hand corner of every page will alert you to any new replies within seconds. You can also use the RSS feed on any questions (bottom right of the question page) to pipe new responses into a RSS reader.