The current flowing through a wire decreases linearly from $10 \text{ A}$ to zero in $4 \text{ s}$. Find the total charge flowing through the wire in the given time interval. (in $text{ C}$)

In conductors,in the absence of an electric field,although electrons are in motion,why is no current formed?

The electric current flowing through a given conductor varies with time as shown in the graph below. The number of free electrons which flow through a given cross-section of the conductor in the time interval $0 \leq t \leq 20 \ s$ is

The relation between the current $i$ (in ampere) in a conductor and the time $t$ (in second) is $i=12 t+9 t^2$. The charge passing through the conductor between the times $t=2 \,s$ and $t=10 \,s$ is (in $C$)

In a hydrogen discharge tube,it is observed that through a given cross-section,$3.13 \times 10^{15}$ electrons are moving from right to left and $3.12 \times 10^{15}$ protons are moving from left to right per second. What is the electric current in the discharge tube and what is its direction?

Define electric current and explain it. Write its $SI$ unit.