An electron revolves $6 \times 10^{15}$ times per second in a circular loop. The current in the loop is:

An electron (charge $= 1.6 \times 10^{-19} \text{ C}$) is moving in a circle of radius $5.1 \times 10^{-11} \text{ m}$ at a frequency of $6.8 \times 10^{15} \text{ rev/s}$. The equivalent current is approximately:

Define $1 \ Coulomb$ in terms of $1 \ Ampere$.

The quantity $X = \frac{\varepsilon_0 LV}{t}$,where $\varepsilon_0$ is the permittivity of free space,$L$ is length,$V$ is potential difference,and $t$ is time. The dimensions of $X$ are the same as those of:

The electric current through a wire varies with time as $I = I_0 + \beta t$,where $I_0 = 20 \ A$ and $\beta = 3 \ A/s$. The amount of electric charge that crosses through a section of the wire in $20 \ s$ is: (in $C$)

When is an electric current produced? Explain.