Question

Derive the units for specific resistance of a solution.

Answer 1

The resistance of a conductor is directly proportional to its length l and inversely proportional to its area of cross sectionA, i.e.,

R ∝ l and R ∝ `1/A`

Thus, R ∝ `1/A` or R = `rho l/A`    ...(i)

Where, ρ (rho) is the constant of proportionality and is called the specific resistance of the conductor.

If l = 1 cm, A = 1 cm²; then equation (i) becomes,

R = ρ

R = ohm cm

∴ The units for specific resistance of a solution is ohm cm.