Compute the resistance in ohms of a copper block 5.0 cm long and 0.10 cm2 in cross-sectional area. (ρ = 1.77 * 10-6 ohm-cm)

R=ρ l/a

l=5 cm

a=0.10 cm²

ρ=1.77*10∧-6 Ωcm

R = (1.77*10∧-6) * 5/0.10

=8.85 * 10∧-5 Ω

resistance is directly proportional to length and inversly proportional to area of cross section is given by above equation