original_query: What is the definition of the amount of charge in 1 electron in the SI system of units?
query: What is the definition of the amount of charge in 1 electron in the SI system of units?
answer: The amount of charge in 1 electron (elementary charge) is defined as a fundamental constant in the SI system of units (effective from 20 May 2019).  Its value, when expressed in coulombs, is exactly 1.602176634 × 10⁻¹⁹ C.