Beginning actors often want to know how long it will be before they hear the results of an audition they have done . There is no set time that they can depend on. Often casting directors and directors take their time in making up their minds about casting, so it could be a number of weeks before you hear if you hear at all.
Most often when you are not selected, you never hear from the casting director. They are very busy and have not the time to contact every actor who auditioned. Thus, they only cast those who are selected or have call backs.
Unless you have specifically been told to do so, never call the casting director for information. If they want to talk to you, they will call you. What do you do, then, while you are waiting for the results? Since most often there won't be any results, the best thing to do after an audition is to forget about it and get on with your acting experience and training. If you don't get it, they will probably not contact you. and if you get a call back, it will be a great surprise and you can go on from there.