Topic: Material Science
In a specimen of ferromagnetic material with saturation magnetization as 8000 Gauss, as the flux density is increased from 0 to 2.5 T, $\mu_{r}$ will
- A. Increase
- B. Decrease
- C. First decrease then increase
- D. First increase then decrease
Answer: D. First increase then decrease
Explanation: From the B-H curve of a ferromagnetic material, the relative permeability $\mu_{r}$ is proportional to the slope ($B/H$). Initially, as H increases, the slope steepens ($\mu_r$ increases) until it reaches the knee of the curve, after which the material begins to saturate and the slope flattens ($\mu_r$ decreases).