A current carrying solenoid of cross-sectional area \( 2\,\mathrm{cm^{2}} \) and 2000 turns has a magnetic moment of \( 0.80\,\mathrm{A\,m^{2}} \). The current flowing through the solenoid is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → \( 2\,\mathrm{A} \)
A solenoid of \( N \) turns behaves as \( N \) current loops in series, so its magnetic moment is \( m = N I A \).
\( \displaystyle I = \frac{m}{N A} \)
\( \displaystyle A = 2\,\mathrm{cm^{2}} = 2\times10^{-4}\,\mathrm{m^{2}} \)
\( \displaystyle I = \frac{0.80}{2000 \times 2\times10^{-4}} = \frac{0.80}{0.40} = 2\,\mathrm{A} \)