Question

a copper wire of cross-sectional area 2.0mm

Answer 1

can you please make your question complete?

Answer 2

a copper wire of cross-sectional area 2.0mm square carries a current of 10 amperes. How many electrons pass though in one second?

Answer 3

you should post this question in the physics section next time...
but hold on and let me see whether i can help.

Answer 4

if a current of 10A is passing through the wire...
it means that 10Coulombs of charge is passing through the wire every second..
so to find the number of electrons found in the 10Coulombs,
divide the 10Coulombs by the charge on 1 electron...

Answer 5

@elenayinglu
do you understand what i just said??