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)

$3.6$J $T^{-1}$

Here, $N=3000$, $A=2\times {10}^{-4}{m}^2,I=6$A

$\therefore$ M$=$NIA$=3000\times 6\times 2\times {10}^{-4}=3.6$J $T^{-1}$.