PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Magnetism and Electromagnetism · Magnetism and Electromagnetism
Problem
Two cylindrical rods, X and Y, are made from different ferromagnetic materials but have identical dimensions: length 10.0cm and cross-sectional area 1.0cm2. When each rod is placed in a steady, uniform magnetic field of 0.35T, rod X reaches magnetic saturation in 0.10s, whereas rod Y requires 5.0s to reach its (lower) saturation magnetization.
Answer the following.
(1) Identify which rod is likely composed of soft iron and which of hard steel. Support your answer with reasoning based on domain behavior.
(2) The saturation magnetization of rod X is measured to be 1.2×106Am−1. Calculate the approximate magnetic dipole moment of rod X when saturated.
(3) Discuss how the hysteresis characteristics of rod X make it preferable to rod Y for use as the core of an electromagnet that is rapidly switched on and off in an AC relay.