i did this experiment under that topic.........i built a basic transistor amplilfier known as common emitter amplifier and after connecting every thing i was asked to change the tranisistor with a tranistor of exactly the same type and get the value 4 d base, emitter and collector ................on doing this, there was little or no diffrence and i am asked to comment on it

 

Without a schematic, it's hard to see if there might be something remarkable about the change. Do you have spec's on the two transistors?

 

get the value 4 d base, emitter and collector

I don't understand. Did you read 4Vdc on each lead? If so, the leads were apparently shorted together.

 

Troubleshooting is not always easy! Maybe one of the Resitors or other parts is shorted or open?