Tesla (unit)
The tesla (symbol T) is the SI derived unit used to measure magnetic fields. Tesla can be measured in different ways; for example, one tesla is equal to one weber per square meter.
The tesla was first defined in 1960 by the General Conference on Weights and Measures (CGPM).^{[1]} It was named in honor of the physicist, electrical engineer, and inventor, Nikola Tesla.
Definitions
Using only the seven base SI units, the definition of a tesla is:
- <math>\mbox{T}
= \dfrac{\mbox{kg}}{\mbox{A} \cdot \mbox{s}^2} </math>
Using other SI derived units, a tesla is also equal to:
- <math>\mbox{T}
= \dfrac{\mbox{V} \cdot \mbox{s}}{\mbox{m}^{2}} = \dfrac{\mbox{N}}{\mbox{A} \cdot \mbox{m}} = \dfrac{\mbox{Wb}}{\mbox{m}^{2}} = \dfrac{\mbox{kg}}{\mbox{C} \cdot \mbox{s}} = \dfrac{\mbox{N} \cdot \mbox{s}}{\mbox{C} \cdot \mbox{m}} </math> The units used are:
A = ampere
C = coulomb
kg = kilogram
m = meter
N = newton
s = second
T = tesla
V = volt
Wb = weber
A tesla is also equal to 10,000 (10^{4}) gauss in the CGS system of units.
Example values
- 3.1×10^{−5}–5.8^{-5} T – the Earth's magnetic field at its surface
- 5×10^{-3} T – the strength of a typical refrigerator magnet
- 0.3 T – the strength of solar sunspots
- 1.25T – the strength of the surface of a neodymium magnet
- 1.5−3 T – strength of medical magnetic resonance imaging systems
- 4 T – strength of the superconducting magnet built around the CMS detector at CERN^{[2]}
- 13 T – strength of ITER fusion reactor^{[3]}
- 16 T – magnetic field strength required to levitate a frog as part of an Ig Nobel Prize winning project.^{[4]}
References
- ↑ International Bureau of Weights and Measures (1960), Système International d'Unités (International System of Units). 11^{th} session, Resolution 12.
- ↑ Taylor, Lucas (23 November 2011). "Superconducting Magnet in CMS". European Laboratory for Particle Physics. Retrieved 5 April 2013.
- ↑ "ITER - the way to new energy". Retrieved 19 April 2012.
- ↑ Berry, M.V. and A.K. Geim (1997). "Of flying frogs and levitrons". European Journal of Physics 18 (4). https://www.ru.nl/publish/pages/682806/frog-ejp.pdf. Retrieved 5 April 2013.