A potential difference of 3 V is applied across a conductor of resistance \( 1.5\,\Omega \). The number of electrons flowing through it in one second would be: (Given charge of an electron, \( e = 1.6 \times 10^{-19}\,\mathrm{C} \))
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → \( 1.25 \times 10^{19} \)
Ohm's law gives the current, and the current is the charge passing per second; each electron carries charge \( e \).
\( \displaystyle I = \frac{V}{R} = \frac{3\,\mathrm{V}}{1.5\,\Omega} = 2\,\mathrm{A} \)
In one second the charge passing is \( q = I t = 2\,\mathrm{C} \).
\( \displaystyle n = \frac{q}{e} = \frac{2\,\mathrm{C}}{1.6\times10^{-19}\,\mathrm{C}} = 1.25\times10^{19} \)