Lowers Recommended Lead-Level Limits in Children. For the first time in 20 years, federal health authorities have lowered the recommended limit for lead exposure in young children, which they say could add 200,000 children to those believed to have unsafe lead levels in their blood.
Electrical Units of Measure. The standard SI units used for the measurement of voltage, current and resistance are the Volt [ V ], Ampere [ A ] and Ohm [ Ï ] respectively.
The electrical resistance of an electrical conductor is a measure of the difficulty to pass an electric current through that conductor. The inverse quantity is electrical conductance, and is the ease with which an electric current passes. Electrical resistance shares some conceptual parallels with the notion of mechanical friction. The SI unit of electrical resistance is the ohm (Ï), while electrical conductance is measured in siemens (S). An object of uniform cross section has a resistance proportional to its resistivity and length and inversely proportional to its cross-sectional area.