Magnetic Field Strength

Definition

Magnetic field strength, also known as magnetic flux density or magnetic induction, is a measure of the force exerted by a magnetic field on a moving charged particle or a current-carrying conductor. It is a fundamental concept in the study of electromagnetism and is crucial in understanding the behavior of charged particles and the interactions between magnetic fields and matter.

5 Must Know Facts For Your Next Test

1. Magnetic field strength is measured in units of tesla (T) or newtons per ampere-meter (N/A⋅m), and it represents the force per unit charge or per unit current.
2. The motion of a charged particle in a magnetic field is determined by the magnetic field strength, the charge of the particle, and the velocity of the particle.
3. In the context of magnetism in matter, the magnetic field strength influences the alignment and behavior of magnetic domains within materials, which determines the overall magnetic properties of the substance.
4. Mutual inductance, which is the phenomenon where a changing current in one circuit induces a voltage in another circuit, is directly related to the magnetic field strength between the two circuits.
5. The strength of a magnetic field decreases with the square of the distance from the source, following an inverse-square relationship.

Review Questions

• Explain how the magnetic field strength affects the motion of a charged particle in a magnetic field.
  • The magnetic field strength, along with the charge and velocity of the particle, determines the Lorentz force exerted on the charged particle. This force is perpendicular to both the direction of the particle's motion and the direction of the magnetic field. The stronger the magnetic field strength, the greater the Lorentz force, which causes the charged particle to experience a greater deflection or change in its trajectory as it moves through the magnetic field.
• Describe the role of magnetic field strength in the context of magnetism in matter.
  • The magnetic field strength influences the alignment and behavior of magnetic domains within materials, which determines the overall magnetic properties of the substance. In diamagnetic materials, the magnetic field strength causes the magnetic domains to align in opposition to the applied field, resulting in a weak repulsive effect. In paramagnetic materials, the magnetic field strength causes the magnetic domains to align with the applied field, resulting in a weak attractive effect. In ferromagnetic materials, the magnetic field strength can cause the magnetic domains to align and amplify the overall magnetic field, leading to strong magnetic properties.
• Analyze the relationship between magnetic field strength and mutual inductance.
  • Mutual inductance is the phenomenon where a changing current in one circuit induces a voltage in another circuit, and this effect is directly related to the magnetic field strength between the two circuits. The stronger the magnetic field strength, the greater the mutual inductance between the circuits, which means that a change in current in one circuit will induce a larger voltage in the other circuit. This relationship is crucial in the design and operation of transformers, where the magnetic field strength between the primary and secondary windings determines the voltage transformation ratio.

Related terms

Magnetic Flux: The total number of magnetic field lines passing through a given surface or area, representing the overall strength of the magnetic field in that region.

Magnetic Permeability:

A measure of the ability of a material to support the formation of a magnetic field within itself, which determines how a magnetic field will interact with that material.

Lorentz Force:

The force exerted on a moving charged particle by a magnetic field, which is perpendicular to both the direction of the particle's motion and the direction of the magnetic field.