magnetic constant
C2Technical / Scientific
Definition
Meaning
A fundamental physical constant (μ₀) that characterizes the strength of the magnetic force in a vacuum.
In physics, the magnetic constant (also known as the permeability of free space) is the measure of the ability of a vacuum to support a magnetic field. It appears in Maxwell's equations and defines the relationship between magnetic induction and magnetic field strength.
Linguistics
Semantic Notes
This is a highly specialized term used almost exclusively in physics and engineering contexts. It is a defined constant, not a variable property. It is often introduced alongside the electric constant (ε₀) and the speed of light (c).
Dialectal Variation
British vs American Usage
Differences
No significant lexical or conceptual differences. The term is standard in the international scientific community.
Connotations
Purely technical and precise in both varieties.
Frequency
Equally rare and specialized in both UK and US English, confined to advanced physics and engineering discourse.
Vocabulary
Collocations
Grammar
Valency Patterns
The magnetic constant [is defined as...][Using/With] the magnetic constant μ₀, one can calculate...The value of [the] magnetic constant is...[This force] depends on the magnetic constant.Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “N/A”
Usage
Context Usage
Business
Not used.
Academic
Core term in advanced physics and electrical engineering courses and literature.
Everyday
Virtually never used.
Technical
Essential in electromagnetic theory, antenna design, and the derivation of formulas for magnetic force and inductance.
Examples
By Part of Speech
verb
British English
- N/A
American English
- N/A
adverb
British English
- N/A
American English
- N/A
adjective
British English
- The magnetic-constant value is exactly defined in the SI system.
- We need the magnetic-constant term for this derivation.
American English
- The magnetic constant value is fixed by definition.
- This is a magnetic constant calculation.
Examples
By CEFR Level
- N/A
- N/A
- In physics, some numbers never change, like the magnetic constant.
- The magnetic constant, denoted μ₀, is a fundamental parameter in electromagnetism.
- The force between two currents depends on the magnetic constant and the geometry of the wires.
Learning
Memory Aids
Mnemonic
Think of 'μ₀' as the 'magnetic muscle' of empty space – it sets the baseline strength for magnetic interactions where there is no material.
Conceptual Metaphor
A RULER FOR FORCE: The constant acts as a fixed scale or ruler that measures how strong a magnetic field can be generated by a given electric current in a vacuum.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid translating 'constant' as 'константный' (which implies 'unchanging' as a quality). Use the noun 'константа' (магнитная постоянная).
- Do not confuse with 'magnetic field constant' or other similar phrases; 'magnetic constant' refers specifically to μ₀.
Common Mistakes
- Pronouncing 'constant' with stress on the second syllable (/kənˈstænt/). The correct stress is on the first syllable for the noun.
- Using 'magnetic constant' to refer to other magnetic properties like susceptibility.
- Omitting the subscript zero (μ₀), which is a crucial part of its notation.
Practice
Quiz
What is the primary context for using the term 'magnetic constant'?
FAQ
Frequently Asked Questions
In the SI system, μ₀ is defined as 4π × 10⁻⁷ N/A² (newtons per ampere squared).
No. The magnetic constant (μ₀) is the permeability of free space (a vacuum). The permeability of a material (μ) is often given relative to μ₀ as μ = μᵣμ₀, where μᵣ is the relative permeability.
It is one of the fundamental constants that link electricity and magnetism. It appears in the law for the force between currents (Ampère's force law) and in the definition of the ampere.
Yes, its SI unit is the henry per metre (H/m), which is equivalent to newtons per ampere squared (N/A²).