If an electron revolves in a circular path of radius $0.5 \times 10^{-10} \ m$ at a frequency of $5 \times 10^{15} \ Hz$,the electric current in the circle is .................. $mA$. (Charge of an electron $= 1.6 \times 10^{-19} \ C$)

$A$ current of $1\, mA$ is flowing through a copper wire. How many electrons will pass a given point in one second?

The current in a conductor is expressed as $I = 3t^2 + 4t^3$,where $I$ is in Ampere and $t$ is in second. The amount of electric charge that flows through a section of the conductor during $t = 1 \ s$ to $t = 2 \ s$ is . . . . . . $C$.

$62.5 \times 10^{18}$ electrons per second are flowing through a wire of area of cross-section $0.1 \, m^2$. The value of the current flowing will be ............ $A$.

$A$ 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 ............... $C$.

$A$ current of $5\,A$ flows through a resistance of $10\, \Omega$ for $4$ minutes. The total charge in Coulombs and the number of electrons passing through any cross-section of the resistor in this time are, respectively: