Hi Amit, This is your new learning friend! https://books.google.com/ngrams It tells you how frequently certain phrases appear in literature. It's a good way of telling how common similar phrases are. I had a play with it, and "impressed by" is slightly more common. In US English, the usage is even more equal to "impressed with". The really interesting thing is that "impressed with" was much more common until about 1900-1920, when both prepositions were used equally.

Hi Amit, Michael is right! We use impressed by when you are referring to yourself being impressed by something ( eg I was impressed by what you said ) and "impressed with" when someone else is impressed with you ( eg he was impressed with your performance)

Hi Amit In the examples you have given (which are active voice) both prepositions are commonly used and it's a matter of preference which one to employ. But in a passive-voice sentence you must use "with". You impressed me by your honesty. - WRONG You impressed me with your honesty. - CORRECT