What is a colulomb?

Answer 1

Coulomb is the unit of electric charge is SI system of units. One coulomb is that charge which when placed from a similar charge in free space at a distance of one meter would repel with a force of 9 x 109 N

Answer 2

A coulomb is the SI unit of electric charge, denoted by the symbol "C". One coulomb is equivalent to the amount of charge transferred by a current of one ampere in one second. It is named after the French physicist Charles-Augustin de Coulomb.