CLASS B AIRSPACE PENETRATION.

Narrative

WHILE INSTRUCTING IN A PIPER SEMINOLE; I HAD A SIT OCCUR THAT IS IN A GRAY AREA OF THE FAR'S. MY STUDENT AND MYSELF HAD JUST FINISHED OUR SECOND OF 2 REQUESTED INSTRUMENT APCHS AT TEB. ON THE BEGINNING OF THE SECOND APCH THEY CLRED US TO ENTER THE CLASS 'B' AIRSPACE. AFTER FINISHING THIS SECOND APCH; I TOLD TETERBORO TWR THAT WE WOULD DEPART THE AREA TO THE NW. THEY TOLD ME TO STAY ON THE SAME SQUAWK (WHICH WAS ISSUED BY APCH) AND CLRED AS REQUESTED. WE CONTINUED TO CLB TO 2000 FT AND BEFORE I HAD NOTICED WE MIGHT HAVE SKIRTED THE EDGE OF THE CLASS 'B' BY TETERBORO WHICH IS 1800 FT. I IMMEDIATELY TOOK ACTION AND REDUCED OUR ALT BACK TO 1700 FT. IF WE DID ENTER; IT WAS LESS THAN 15 SECONDS. THE REASON MY ATTN WAS DISTRACTED; WAS DUE TO ME INCREASING THE PWR ON THE SIMULATED ENG OUT SLOWLY TRYING NOT TO OVER STRESS THE ENG SINCE IT WAS MINUS 5 DEG C. I CALLED A PLT'S ORGANIZATION AND ASKED THEM SINCE I WAS IN A RADAR ENVIRONMENT AND STILL SQUAWKING THE SAME CODE; WAS I LEGAL TO RE-ENTER THE CLASS 'B' WHILE DEPARTING THE AREA. THEY COULD NOT GIVE ME AN ANSWER.