Q.In an atom electron is moving with the speed of $6.6 \times 10^4$ ms$^{-1}$ in the orbit of radius 0.7 Å. Find the equivalent current in the orbit.

Electric Current and Charge Flow

Electric current is the rate of flow of charge across a section of a conductor. For a steady flow $I = q/t$; in general it is the instantaneous derivative

so if the charge is given as a function of time, e.g. $q=3t^2+t$, the current at any instant is its time‑derivative. Conversely the charge transported between $t_1$ and $t_2$ is the integral $q=\int_{t_1}^{t_2} I\,dt$. Current is a scalar quantity even though it has a sense of flow, whereas current density $\vec{J}$ is a vector. …