Question

Solve this:

1. A north pole of strengt $\mathrm{\pi }$ A m, is moved around a circle of radius 10 cm which lies around a long straight conductor carrying a current of 10 A. The work done is nearly
$\left(1\right)4\mathrm{\mu J}\left(2\right)40\mathrm{\mu J}\left(3\right)400\mathrm{\mu J}\left(4\right)0.4\mathrm{\mu J}$

Answer 1

Dear Student,
$$\begin{gathered} Magneticfieldduetowireatdis\tan cer=\frac{{\mu }_{0}I}{2\pi r} \\ andforceonmagneticpoleofstrength\left(m\right)=\pi Am \\ sonowforceonthepole=\frac{{\mu }_{0}I}{2\pi r}\times \pi \\ andnowworkdone=F.d=\frac{{\mu }_{0}I}{2\pi r}\times \pi \times 2\pi r=\pi {\mu }_{0}I=4{\pi }^2\times {10}^{-7}\times 10=40\mu J \end{gathered}$$
Regard