Question

An iron rod is placed parallel to the magnetic field of intensity 2000 A/m. The magnetic flux through the rod is $6\times {10}^{-4}Wb$ and its cross-sectional area is 3 cm${}^2$. The magnetic permeability of the rod in $\frac{Wb}{A-m}$ is:

• A. ${10}^{-1}$
• B. ${10}^{-2}$
• C. ${10}^{-3}$
• D. ${10}^{-4}$

Answer 1

The correct option is C ${10}^{-3}$

Cross-sectional area $A=3\times {10}^{-4}{m}^2$

Magnetic flux through the rod $\varphi =6\times {10}^{-4}Wb$

Magnetic field intensity $H=2000$ A/m

Using $\varphi =BA$ and $B=\mu H$

We get magnetic permeability $\mu =\frac{\varphi }{AH}$

$\therefore$ $\mu =\frac{6000}{3\times {10}^{-4}\times 2000}={10}^{-3}$ $\frac{Wb}{A-m}$