Fundamental constants: e 1.60 x 1019 c - elementary charge me 9.11 x 1031 kg - electron mass 1. the intrinsic concentration of charge carriers in crystalline germanium is 2.0 x 1019 m3. the mobility of electrons is ue = 0.39 m2/(v s) 0.19 m2/(v s). ni and the mobility of "holes" is h (a) estimate the relaxation time t for electrons in crystalline germanium. (b) calculate the electric conductivity of crystalline germanium. (c) calculate the resistance r of a cylindric rod made of crystalline ger- manium that has diameter d = 5 mm and length 20 mm.