What happens if we force a voltage on Vbe of a bjt transistor
You can't make Vbe larger than 0.7V without destroying the transistor.

As long as the current is low enough to not damage the transistor, the voltage drop on Vbe will be 0.7V.

If you measure more than 0.7V from the base to the emitter of a bipolar junction transistor (BJT,) then you have destroyed it.

Between the base and the emitter of a BJT is the equivalent of a diode.  That's why Vbe is 0.7V - it is the foward voltage of a silicon diode.

Just like any diode, the forward voltage stays around 0.7V unless it is damaged.

So, no, you can't "force" Vbe to be higher than 0.7V if you want to actually use it as a transistor afterwards.



I've been reminded that not everyone will realize that "0.7V" is a sort of shorthand for "the rated Vbe of your transistor."

Depending on how the transistor is made, Vbe can be higher or lower than 0.7V.  It also varies depending on forward current and temperature just like in any other diode.

In any case, the actual Vbe is inherent to the diode and the current through it.  If you try to force any higher voltage onto it then you will destroy it.