Ohm
Figure 1. A carbon resistor[1] with the resistance of 2 MΩ, the colour code gives the resistance in Ohms.
The Ohm (Ω) is a unit of electrical resistance, useful for measuring the resistance of resistors, conductors, or even electrical insulators. The unit can be thought of as amperes/volts.
Measurements of resistance go from 0 Ω for superconductors to ~ for a cm block of metal like copper or aluminum up to ~
for a block of sulfur. Very few physical measurements have spanned 25 orders of magnitude like this (for length that's a ratio of the thickness of a fingernail to the size of a galaxy)!
To learn more about the Ohm please see Dr. Rowlett's dictionary of units.
References
- ↑ http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/rescarb.html accessed Dec. 7th 2014.