If all your homework and tests are online, you should be fine.
You have a good web browser with the ipad
, so you could do almost anything on the ipad you could do with your laptop.
You will have trouble with some online video and games, though, as the ipad doesn't support flash. Also, the ipad likely has less system resources than your laptop, so you will have difficulty running lots of apps at a time, and some pages might run more slowly than on your laptop.
Also, the ipad isn't really ideal for word processing. But if you're okay with that, you will be fine doing your homework on the ipad :)