To help compare different orders of magnitude, this page lists lengths between 10â5 m and 10â4 m (10 Âµm and 100 Âµm). 10 Âµm â width of cotton fibre. 10 Âµm â transistor width of the Intel 4004, the world's first commercial microprocessor. 10 Âµm â mean longest dimension of a human red blood cell.