Question

how many electrons make 3micro. colymb of charge​

Answer 1

1.6×10^-19 C charge possesed by 1

electron

1 C charge is there in - 1/ 1.6×10^-19

10^-6 C or 1 micro Coulomb in - 10^-3/ 1.6×10^-19

So

3 micro Coulomb charge will be in 3× 10^-3 /(1.6×10^-19) = 1.875× 10^13 electrons