Henry (unit) of conductors, such as parallel wires, or a solenoid. A small air-core coil used for broadcast AM radio tuning might have an inductance of a few tens of microhenries. A large motor winding with many turns around an iron core may have an inductance of scores or hundreds of henries. The physical size of an inductance is also related to its current carrying and voltage withstand ratings. Henry (unit) The henry (symbol: H) is the SI derived unit of electrical inductance. If a current of 1 ampere flowing through the coil produces flux linkage of 1 weber turn, the coil
Einstein (unit) Einstein (unit) The einstein is a unit defined as one mole () of photons. As such, photosynthetically active radiation (PAR) was formerly often reported in microeinsteins per second per square meter (μE m s). This usage is also not part of the International System of Units and when used this way it is redundant with the mole. Since the unit does not have a standard definition and is not part of the SI system, it is usually better to avoid its use. The same information about photosynthetically active radiation can be conveyed using the SI convention by stating something such