# In a Hydrogen atom, an electron moves in an orbit of radius $5 \times 10^{-11}m$ with a speed of $2.2 \times 10^6 m/s.$ Calculate the equivalent current.

$\begin {array} {1 1} (A)\;1.12mA & \quad (B)\;0.12mA \\ (C)\;1.2mA & \quad (D)\;0.112mA \end {array}$

Current = charge flowing per unit time = charge times the angular frequency
It reduces to the following formula
$I = \large\frac{qv}{2 \pi r}$
Substituting the values in the above formula yields the final answer.
Ans : (A)
edited Mar 14, 2014