The relation between $\mu$ and $H$ for a specimen of iron is $\mu=\left[\frac{0.4}{H}+12 \times…

The relation between $\mu$ and $H$ for a specimen of iron is $\mu=\left[\frac{0.4}{H}+12 \times 10^{-4}\right] \mathrm{Hm}^{-1}$. The value of H which produces flux density of 1 T will be ( $\mu=$ magnetic permeability, $\mathrm{H}=$ magnetic intensity)
  1. $250 \mathrm{Am}^{-1}$
  2. $500 \mathrm{Am}^{-1}$
  3. $750 \mathrm{Am}^{-1}$
  4. $10^3 \mathrm{Am}^{-1}$

Solution

For iron specimen, $\begin{aligned} & \mu=\left[\frac{0.4}{\mathrm{H}}+12 \times 10^{-4}\right] \mathrm{H}_{\mathrm{m}^{-1}}, \mathrm{~B}=1 \mathrm{~T} \\ & \therefore \quad \mathrm{~B}=\mu \mathrm{H}=0.4+\left(12 \times 10^{-4}\right) \mathrm{H} \\ & \Rightarrow 1=0.4+12 \times 10^{-4} \mathrm{H} \\ & \therefore \mathrm{H}=500 \mathrm{Am}^{-1}\end{aligned}$

Asked in: AP EAMCET 2024 (23 May Shift 1)

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