The charge of an electron is $1.6 \times 10^{-19} \ C$. How many electrons strike the screen of a cathode ray tube each second when the beam current is $16 \ mA$?

$62.5 \times 10^{18}$ 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 ............ $A$.

Explain the current formed in solid conductors in the presence of an external electric field.

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 $= 1.6 \times 10^{-19} \ C$)

$A$ copper rod of cross-sectional area $A$ carries a uniform current $I$ through it. At temperature $T$,if the volume charge density of the rod is $\rho$,how long will the charges take to travel a distance $d$?

The charge on a capacitor plate in a circuit,as a function of time,is shown in the figure. What is the value of current at $t = 4 \, s$ ? ............... $\mu A$