bar magnet
Học thuậtThân thiện
Definition
Noun: A bar magnet is a permanent magnet shaped as a rectangular bar. Its defining characteristic is that it has two distinct magnetic poles, one at each end, conventionally labeled the north-seeking pole and the south-seeking pole.
Usage
The term bar magnet is used to describe a specific, common physical object used to demonstrate magnetic principles. It is a fundamental tool in physics education and experiments. - It is typically made from a ferromagnetic material like iron, steel, or a ceramic compound. - Its magnetic field lines emerge from the north pole, curve around the magnet, and re-enter at the south pole.
Examples
Advanced Usage
- Magnetic Dipole Moment: In physics, a bar magnet is often treated as a simple magnetic dipole, a fundamental model for understanding magnetic fields and torque in a uniform field.
- Educational Model: The bar magnet serves as the primary conceptual model for explaining attraction, repulsion, magnetic poles, and field lines before introducing more complex magnetic shapes like horseshoe magnets or electromagnets.
Variants and Related Words
- Magnet (n): The general term for any object that produces a persistent magnetic field.
- Horseshoe Magnet (n): A magnet bent into a U-shape, bringing the poles closer together to create a stronger magnetic field in the gap.
- Permanent Magnet (n): A magnet that retains its magnetic properties in the absence of an inducing field or current, like a typical bar magnet.
Synonyms
- Rectangular magnet
- Magnetic bar
Related Phrases and Concepts
- Magnetic poles: The two ends of a bar magnet where the magnetic force appears strongest.
- Like poles repel, unlike poles attract: The fundamental law of magnetism easily demonstrated with two bar magnets.
- Magnetic field lines: The invisible lines of force that can be visualized using iron filings around a bar magnet.
Noun
- a magnet in the form of a bar with magnetic poles at each end