The length of germanium rod is 2 cm and its area of cross section is 2 mm2. If for germanium ni=2.5x1019m-3 , μe=0.39m2v-1s-1, μh=0.19m2v-1s-1. Its resistance in ohms is
Resistance=R =ρlA=1σlA =lnie(μe+μh)A
=2×10−22.5×1019×1.6×10−19(0.39+0.19)2×10−6 =4310.34Ω