Question

A magnetising field of $1600\, A\, m^{-1}$ produces a magnetic flux of $2.4 × 10^{-5}\, Wb$ in an iron bar of cross-sectional area $0.2\, cm^2$. The susceptibility of an iron bar is

• A. 298
• B. 596
• C. 1192
• D. 1788

Answer 1

Answer: (B)

Here, $H = 1600\, A\, m^{-1},$
Magnetic flux $\left(\phi\right)=2.4\times10^{-5}\,Wb$
$A=0.2\,cm^{2}=0.2\times10^{-4}\,m^{2}$
$\therefore B=\frac{\phi}{A}=\frac{2.4\times10^{-5}}{0.2\times10^{-4}}=1.2\,Wb\,m^{2}$
$\therefore \mu=\frac{B}{H}=\frac{1.2}{1600}=7.5\times10^{-4}\,N\,A^{-2}$
Hence, susceptibility $\chi=\frac{\mu}{\mu_{0}}-1=\frac{7.5\times10^{-4}}{4\pi\times10^{-7}}-1=596$