Number of electrons flowing per second in a conductor carrying a current of $9 \,A$ is

An electron moves with a constant speed of $4 \times 10^6 \, m/s$ in a circle of radius $10 \, cm$. Find the electric current at any point on the circle.

The electric current in a wire varies with time as $i = (2 + 3t) \text{ A}$. Calculate the charge that passes through the cross-section of the wire in $10 \text{ s}$.

Across a metallic conductor of non-uniform cross-section, a constant potential difference is applied. The quantity which remains constant along the conductor is

The current flowing through a wire depends on time as $I = 3t^2 + 2t + 5$. The charge flowing through the cross-section of the wire in the time interval from $t = 0$ to $t = 2 \ s$ is: (in $C$)

$A$ source of $e.m.f.$ $E = 15\,V$ and having negligible internal resistance is connected to a variable resistance so that the current in the circuit increases with time as $i = 1.2t + 3$. Then,the total charge that will flow in the first five seconds will be ............... $C$.