Question

A copper wire has cross sectional area of 6.7 × 10-8 m2and is 1 m long. Calculate the current flowing in the wire if the wire is connected to a 9 V battery. The resistivity of copper is given as 1.68 × 10-8 Ω·m

Answer 1

R = ρ L/ A

Where;

ρ= resistivity = 1.68 x 10^-8 OHM m

L= lenght = 1 m

A = cross sectional area = 6.7 × 10-8 m2

R = resistance

R = 1.68 x 10^-8 OHM m ( 1 m/ 6.7 × 10-8 m2)

R = 0.25 OHM

OHM's LAW

V = IR

V= 9 V

I = V / R = 9 / 0.25 = 36 Ampere