SI Units Analysis: Identifying Non-Base Units

The International System of Units (SI) comprises seven fundamental base units. We need to identify which of the given options is not among them.

SI Base Units Reference

• Metre (\(m\)) for length
• Kilogram (\(kg\)) for mass
• Second (\(s\)) for time
• Ampere (\(A\)) for electric current
• Kelvin (\(K\)) for temperature
• Mole (\(mol\)) for amount of substance
• Candela (\(cd\)) for luminous intensity

Evaluating the Options

• Metre: Is the SI base unit for length.
• Kilogram: Is the SI base unit for mass.
• Ampere: Is the SI base unit for electric current.
• Coulomb (\(C\)): Represents electric charge. It is defined as the amount of electric charge transported by a constant current of one Ampere in one second (\(1 \, C = 1 \, A \cdot s\)). Since it can be expressed in terms of other base units (Ampere and Second), it is a derived unit, not a base unit.

Final Determination

Metre, Kilogram, and Ampere are established SI base units. Coulomb, representing electric charge, is derived from the base units of Ampere and Second.

Therefore, Coulomb is not an SI base unit.