Conductance G = 1/R (Siemens). Conductivity kappa = G * (l/A) = G * cell constant. Molar conductivity Lambda_m = kappa * 1000/C (C in mol/L, giving units S.cm^2/mol). For strong electrolytes: Lambda_m increases slightly with dilution and approaches Lambda_m_infinity linearly (Debye-Huckel-Onsager equation: Lambda_m = Lambda_m_infinity - A*sqrt(C)). For weak electrolytes: Lambda_m increases sharply at high dilution as dissociation increases. Lambda_m_infinity cannot be obtained by extrapolation for weak electrolytes — use Kohlrausch's law instead. Key: kappa decreases with dilution (fewer ions per unit volume), but Lambda_m increases with dilution (more dissociation per mole of solute).