Question

Define unit charge.

Answer 1

Hint: The SI derived unit of quantity of electric charge is the coulomb $\left( {symbol:C} \right)$The coulomb is defined As the quantity of charge that passes through the cross section of an electrical conductor carrying one ampere for one second.

Complete answer:
This unit was proposed in 1946 and ratified in 1948, in modern practice the phrase “amount of charge” is used instead of “quantity of charge”. The lowercase symbol $q$is often used to denote a quantity of electric charge that can be directly measured with an electrometer or indirectly measured with a galvanometer.
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). The value for elementary charge. When expressed in the Si unit for electric charge (coulomb) is exactly $1.602176634 \times {10^{ - 19}}C$
After finding the quantized charge in 1891 George Stoney proposed the unit “electron” for this fundamental unit of electrical charge. This was before the discovery of the partial by J.J Thomson in 1897. The unit is Today referred to as elementary charge. Fundamental unit of charge or simply as e. A measure of charge should be a multiple of the elementary charge. E, even if at large scales charge seems to behave as a real quantity. In some contexts it is meaningful to speak of fractions of a charge; for Example, in the charging of a capacitor or in the fractional quantum hall effect.

Note:
The unit for a day is sometimes used in electrochemistry. One for a day of charge is the magnitude of the charge of one mole of electrons. i.e. $96485,33289\left( {59} \right)C.$
In systems of $Cgs$ electric charge is expressed as a combination of only three Fundamental quantities (length, mass, and time) and not four as in Si where electric charge is a combination of length mass and electric current.