On a magnetization (B–H) characteristic, which two physical quantities are plotted against each other to describe how a material responds to an applied magnetic field?

Introduction / Context:The B–H curve (magnetization curve) is a foundational tool in electromagnetics and power engineering. It captures how a ferromagnetic material's flux density B responds to an applied magnetizing force H. Designers use it to choose cores, estimate saturation, evaluate hysteresis, and calculate losses in transformers and inductors.

Given Data / Assumptions:

• B denotes magnetic flux density, typically in tesla (T).
• H denotes magnetizing force (magnetic field strength), in A/m.
• The graph summarizes material behavior, including linear region, knee (saturation onset), and hysteresis.

Concept / Approach:B–H graphs plot B on the vertical axis and H on the horizontal axis. As H increases, magnetic domains align and B rises until approaching saturation. When H is cycled, the material exhibits a hysteresis loop whose area reflects core loss. Permeability μ relates B and H by B = μ * H in the linear region, but μ itself can be nonlinear and is not directly plotted; instead, it is inferred from the slope dB/dH.

Step-by-Step Solution:Identify axes: vertical = B (flux density), horizontal = H (magnetizing force).Interpret slope: slope = dB/dH = μ (instantaneous or differential).Note features: initial magnetization, knee, and saturation.Understand hysteresis: loop area corresponds to energy loss per cycle.

Verification / Alternative check:Datasheets and core catalogs publish B–H curves or related hysteresis loops. Calculations of inductor volt-seconds and transformer excitation current rely on B–H behavior.

Why Other Options Are Wrong:Reluctance, permeability, and magnetomotive force are derived quantities; they are not the standard axes of the B–H plot.

Flux (Φ) is related to B but is not used on the basic B–H characteristic.

Common Pitfalls:Assuming a constant μ across all H; most ferromagnets are nonlinear, and μ varies with operating point. Always consult the relevant B–H or core data for accurate design.

Final Answer:Flux density and magnetizing force