In hydrogen atom, the electron makes 6.6 × 1015 revolutions per second around the nucleus in an orbit of radius 0.5 × 10−10 m. The equivalent current is nearly:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 1 mA
An electron revolving in an orbit is equivalent to a current loop. The equivalent current is the charge passing a point of the orbit per second, i.e. the charge e times the number of revolutions per second f.
\( I = ef \)
\( I = 1.6\times10^{-19}\,\mathrm{C} \times 6.6\times10^{15}\,\mathrm{s^{-1}} \)
\( I \approx 1.06\times10^{-3}\,\mathrm{A} \approx 1\,\mathrm{mA} \)
The radius is not needed for the current; it would be needed for the magnetic moment \( I\pi r^{2} \).