The maximum amount of working hours in a single day is 24. So long as they pay you the proper overtime you can work as many hours as there are in a day. However, most likely they will not be willing to pay you overtime, so they will most likely only have you work an 8 hour (9 hour, including a lunch hour) shift, but many part-time shifts are only 4-6 hours.
This would be a topic to as your employer though, and as you don't even have an employer yet anything we tell you could change based on who your future employer is.
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So when you're happy (Hurray!), or sad (Aw!),
Or frightened (Eeek!), or mad (Rats!)
An interjection starts a sentence right.