Dear Jadhav,

Since you have asked this question months ago, I hope you have solved this question.

Answering to your question, Considering you are asking about  what fraction of electrons to be removed from the sphere to give it a charge of 2 microcoulomb?

According to the question, Charge on the nucleus of each atom is 29e.

therefore, Net Charge on 2gm copper sphere would be 29e * (2*10^22) = 5.8 * 10^23

Number of electrons to be removed to give 2 microcoulomb charge= q/e which would be 1.25* 10^13.

So, Fraction of electrons to be removed will be 2.16* 10^-11

Good Luck!