As others have already said, it really depends. Some firms will wait till everyone who has done first round in that cycle of recruiting has finished before communicating outcome. This means some people may have to wait 2 weeks, while others only wait 1-2 days. Overall don't stress.
And yes, firms absolutely should let you know outcome, whether positive or negative. In some rare cases firms can mess up and not let candidates know - but this is generally bad practice and shouldn't be expected.