I know can can work for like 20 hours in a week as a student in Canada. Will I be allowed to work for longer hours whena semester has ended?
Here’s the answer to your question according to the Canadian Immigration Authorities:
Once you are authorized to work off-campus, you can work up to 20 hours per week while classes are in session. However, during scheduled breaks such as the summer or winter holidays and spring break, you are allowed to work full-time. You must ensure you comply with the requirements of the off-campus work authorization.
You may continue to work full time after you complete your program, but only if you have submitted an application for a post-graduation work permit, or other work permit.