How can I solve this quesition (physics)?

Question

A wire with a resistance of 8.33 x 10^– 5 ohm/cm carries a current of 1.28 amp.

(a) How many electrons move through the wire per second?
(b) What voltage is required to produce this current through 800-m wire?

Answer 1

a) Current is the rate at which electric charges move through a cross section of wire, or

I (amp) = Q (coulomb) / t (sec)
1.28 = Q / 1
Q = 1.28 coulombs (or 1.28 C)

One electron has a charge of -1.60 x 10^-19 coulombs, so divide the total charge (Q) by the charge per electron to get the number of electrons.

1.28 / 1.60 x 10^-19 = 8.0 x 10^+18 electrons

b) V= IR
First, calculate R: (8.33 x 10^-5) * 80000 cm = 6.664 ohms

V = 1.28 * 6.664 = 8.53 volts

Answer 2

a) # of electrons/sec= I/Qe
I - current in Amps or Coulombs/sec
Qe - charge of an electron in Coulombs = 1.602 E–19 C
so # of electrons/sec= 1.28/1.602 E–19 = 7.99 E+18 electrons

b) V=IR where
R= (8.33 E– 5 ohm/cm ) x (800 x 100)=6.66 ohms
V=IR=1.28 x 6.66=8.52 V