Will the alarm trigger if the trigger Time is set to past Time?
For example, if the current time is 17:00 PM and if I set the alarm as 15:00 which is already passed, will the alarm be triggered?
No it won't.
However, if you set it at 17:00, but have your mobile shut down at that moment, and later start up your mobile at lets say 17:05, then you should get a postponed alarm.