The SI unit of conductance is

The correct answer is Option (3) → S

The conductance (G) of a conductor is the reciprocal of its resistance, G = 1/R. Resistance is measured in ohm (Ω), so the unit of conductance is ohm⁻¹ (mho), whose SI name is the siemens (S).

The related quantities build on this unit:

• Conductivity (κ), the conductance of a 1 m cube: \( \displaystyle \kappa=G\times\frac{l}{A}\ \Rightarrow\ \mathrm{S}\times\frac{\mathrm{m}}{\mathrm{m^2}}=\mathrm{S\,m^{-1}} \)

• Molar conductivity (Λ_m): \( \displaystyle \Lambda_m=\frac{\kappa}{c}\ \Rightarrow\ \frac{\mathrm{S\,m^{-1}}}{\mathrm{mol\,m^{-3}}}=\mathrm{S\,m^{2}\,mol^{-1}} \)

So the SI unit of conductance is S.

NCERT (2026-27 edition):
Conductance of Electrolytic Solutions – …