EMU of current to Teraampere volt per ohm
EMU
TA V/Ω
Conversion History
| Conversion | Reuse | Delete |
|---|---|---|
1 EMU (EMU of current) → 1e-11 TA V/Ω (Teraampere volt per ohm) Just now |
Quick Reference Table (EMU of current to Teraampere volt per ohm)
| EMU of current (EMU) | Teraampere volt per ohm (TA V/Ω) |
|---|---|
| 0.1 | 0.000000000001 |
| 0.5 | 0.000000000005 |
| 1 | 0.00000000001 |
| 5 | 0.00000000005 |
| 10 | 0.0000000001 |
| 30 | 0.0000000003 |
| 100 | 0.000000001 |
About EMU of current (EMU)
The electromagnetic unit (EMU) of current equals exactly 10 amperes, numerically identical to the biot. It is the current unit native to the CGS electromagnetic (CGS-EMU) system, which dominated electrical physics from the mid-19th century until SI adoption in 1960. In CGS-EMU, the permeability of free space is defined as 1, giving the electromagnetic subsystem its characteristic form where magnetic force between parallel currents is expressed purely in dynes. The EMU of current appears in classical electrodynamics texts, historical measurement standards, and theoretical physics work using CGS-EMU conventions. All practical electrical measurement now uses SI amperes.
1 EMU of current = 10 A. A 50 A arc welding process carries 5 EMU. The unit is encountered primarily in pre-1960 scientific literature.
About Teraampere volt per ohm (TA V/Ω)
The teraampere volt per ohm (TA·V/Ω) equals exactly 10¹² amperes, derived from Ohm s law (I = V/R) with a tera- prefix: (volt)/(ohm) = ampere, scaled by 10¹². No natural or engineered system on Earth produces currents remotely approaching one teraampere; the unit exists as a dimensional expression used in extreme theoretical physics, astrophysics (stellar current sheets, pulsar magnetospheres), and unit-conversion pedagogy. The notation makes Ohm s law dimensionally explicit at an extreme scale and serves as a reminder that SI prefixes can be applied consistently to derived units.
One teraampere would require one teravolt across one ohm — voltages found only near highly magnetised neutron stars. The unit is encountered in astrophysics and theoretical electrodynamics rather than any lab or industrial setting.
EMU of current – Frequently Asked Questions
What does EMU stand for and why was it created?
EMU stands for "electromagnetic unit." In the 1860s–1870s, physicists needed separate unit systems for electrostatic and electromagnetic phenomena because they had not yet unified them. The EMU system was built around magnetic force between currents, while the ESU system was built around Coulomb's electrostatic force. The ratio between them turned out to be the speed of light — a clue that led to Maxwell's equations.
Is the EMU of current the same as a biot?
Yes, exactly. Both equal 10 amperes. The biot is the named unit; "EMU of current" is the generic label. It is like saying "SI unit of force" versus "newton" — same thing, different label. The CGS-EMU system also has named units for other quantities: the gauss (magnetic field), the oersted (magnetising field), and the maxwell (magnetic flux).
Why did physics abandon the EMU system?
The EMU system was awkward for practical electrical engineering — 1 EMU of resistance (the abohm) equals 10⁻⁹ ohms, making everyday values absurdly large numbers. The SI system, adopted in 1960, unified mechanical and electrical units into one coherent framework with human-scale values. Practicality won over tradition.
Where might I encounter EMU of current in old scientific papers?
Pre-1960 physics journals, particularly in geomagnetism, plasma physics, and early electrical standards work, routinely use EMU. Geophysicists measuring Earth's magnetic field historically reported results in CGS-EMU units (gauss, oersted, EMU). Some geophysics reference data still has not been converted to SI.
How did the speed of light connect the EMU and ESU systems?
Weber and Kohlrausch discovered in 1856 that the ratio of the ESU to EMU charge was approximately 3×10¹⁰ cm/s — the speed of light. This was no coincidence: Maxwell showed that light is an electromagnetic wave, and the unit ratio reflects the fundamental coupling between electric and magnetic fields. One of the greatest insights in physics history, hidden in a unit conversion.
Teraampere volt per ohm – Frequently Asked Questions
Does anything in the universe carry a teraampere of current?
Possibly. Astrophysical jets from active galactic nuclei are theorised to carry currents of 10¹⁷–10¹⁸ amperes — millions of teraamperes — flowing along magnetic field lines spanning thousands of light-years. Pulsar magnetospheres may sustain teraampere-class currents in their polar regions. On Earth, nothing comes remotely close.
Why write TA·V/Ω instead of just teraampere?
The notation makes the derivation from Ohm's law explicit: I = V/R, scaled by tera. It appears in pedagogical contexts showing that SI prefixes apply consistently to derived expressions, and in astrophysics papers where the V/Ω form reminds readers of the physical relationship producing the current — a voltage driving charge through a resistance.
What voltage would you need to push a teraampere through a wire?
Even through a superconductor (zero DC resistance), you would need enormous energy to establish the magnetic field of a teraampere current. Through a 1 Ω resistor, Ohm's law says you would need 10¹² volts (1 teravolt). The power dissipated would be 10²⁴ watts — about 2.6 million times the Sun's total luminosity. The wire would not survive.
How do astrophysical current sheets reach teraampere scales?
In astrophysical jets and magnetospheres, charged plasma flows along magnetic field lines over enormous cross-sections — millions of square kilometers. Even modest current densities, integrated over these vast areas, yield teraampere total currents. The plasma is the conductor, and the "voltage" comes from the rotating magnetic field of the central object.
Is there any practical unit between megaampere and teraampere?
The gigaampere (GA, 10⁹ A) fills that gap but is almost never used. No terrestrial phenomenon or experiment reaches gigaampere levels. The jump from megaampere (achievable in pulsed-power labs) to teraampere (astrophysical only) reflects a genuine gap in nature — there is simply nothing on Earth that produces currents between 10⁶ and 10⁹ amperes.