Question

A closely wound solenoid of $3000$ turns and area of cross section $2 \times 10^{-4}\, m^2$, carrying a current of $6\, A$ is suspended through its centre allowing it to turn in a horizontal plane. The magnetic moment associated with this solenoid is

• A. $1.2\, J\, T^{-1}$
• B. $2.4\, J\, T^{-1}$
• C. $3.0\, J\, T^{-1}$
• D. $3.6\, J\, T^{-1}$

Answer 1

Answer: (D)

Here, $N = 3000$,
$A = 2 \times 10^{-4}\, m^{2}$,
$I = 6\, A$
$\therefore \quad M = N\, I \,A = 3000 \times 6 \times 2 \times 10^{-4} = 3.6 \,J \,T^{-1}$