Magnetic constants are fundamental values that describe the behavior of magnetic fields in materials and space. The most commonly referenced magnetic constant is the permeability of free space, denoted as μ₀, which quantifies how a magnetic field interacts with a vacuum. It is essential for calculations in electromagnetism and is approximately equal to 4π × 10⁻⁷ T·m/A. Another important magnetic constant is the magnetic susceptibility, which measures how much a material will become magnetized in an external magnetic field. Different materials have varying susceptibilities, influencing their magnetic properties. Understanding these constants is crucial for applications in electromagnetism, magnetic materials, and engineering.