A material of $0.25 \mathrm{~cm}^2$ cross-sectional area is placed in a magnetic field of strength…
A material of $0.25 \mathrm{~cm}^2$ cross-sectional area is placed in a magnetic field of strength $(\mathrm{H}) 1000 \mathrm{Am}^{-1}$. Then, the magnetic flux produced is
(Susceptibility of material is 313)
(Permeability of free space, $\mu_0=4 \pi \times 10^{-7} \mathrm{Hm}^{-1}$ )
$8.33 \times 10^{-8} \mathrm{~Wb}$
$1.84 \times 10^{-6} \mathrm{~Wb}$
$9.87 \times 10^{-6} \mathrm{~Wb}$
$3.16 \times 10^{-6} \mathrm{~Wb}$
Solution
$\begin{aligned} & \text { Magnetic flux } \phi=B A=\mu H A \\ & =\mu_0\left(1+\chi_{\mathrm{m}}\right) H A\left[\because \mu=\mu_0\left(1+\chi_m\right)\right] \\ & =4 \pi \times 10^{-3} \times(1+313) \times 1000 \times 0.25 \times 10^{-4} \\ & =9.87 \times 10^{-6} \mathrm{~Wb}\end{aligned}$