Question

A closely wound solenoid of $1000$ turns and area of cross section $1.4\times {10}^{-4}{m}^2$ carrying a current of $3$ A is suspended through its centre allowing it to turn in a horizontal plane. The magnetic moment associated with this solenoid is

• A. $0.22J{T}^{-1}$
• B. $0.32J{T}^{-1}$
• C. $0.42J{T}^{-1}$
• D. $0.52J{T}^{-1}$

Answer 1

The correct option is C $0.42J{T}^{-1}$

Given data for solenoid,
no. of turns, $n$ = $1000$
Area of cross-section, $A=1.4\times {10}^{-4}{m}^2$
and current, $I=3A$
By using formula for magnetic moment,
$m=nIA$
$\Rightarrow m=1000\times 3\times 1.4\times {10}^{-4}=0.42J{T}^{-1}$
Hence, the correct answer is $\left(C\right)$