Physics - Magnetism Question with Solution | TestHub

Along the equatorial line, magnetic field strength $$B=\frac{{\mu }_0}{4\pi }\frac{M}{(r^2+{\ell }^2{}^{3/2}})$$ Given: $M=4\mathrm{J}{T}^{-1}$ $$r=200\mathrm{cm}=2\mathrm{m}$$ $\ell =\frac{6\mathrm{cm}}{2}=3\mathrm{cm}=3\times 10^{-2}\mathrm{m}$ $$\therefore B=\frac{4\pi \times 10^{-7}}{4\pi }\times \frac{4}{{\left[2^2+{\left(3\times 10^{-2}\right)}^2\right]}^{3/2}}$$ Solving we get, $B=5\times 10^{-8}$ tesla