Which of the following is the symbol for an electric cell?

$1 \, \mu A = \ldots \ldots \ldots \, A$

Which particles are responsible for the flow of current in conductors?

$1\, \mu A = \dots \dots \dots \,mA$

Name and define the $SI$ unit of current. Calculate the number of electrons that flow through a conductor in $1$ second to constitute a current of $1$ ampere. (Charge on an electron $= 1.6 \times 10^{-19} \text{ C}$)

Define current,give its mathematical expression. What is its $SI$ unit?