The length of germanium rod is 0 . 925 cm and its area of cross section is 1 mm 2 . If for germaniun n i = 2 . 5 × 10 19 m - 3 , μ h = 0 . 19 m 2 / v - s , μ e = 0 . 39 m 2 / v - s , then the resistance of the rod is

Step-by-step solution

Conductivity, σ = n e μ ⇒ σ = n e μ e + μ h ⇒ σ = 2 . 5 × 10 19 × 1 . 6 × 10 - 19 × 0 . 19 + 0 . 39 ⇒ σ = 4 0 . 58 = 2 . 32 Resistivity, ρ = 1 σ = 1 2 . 32 = 0 . 431   Ω Resistance, R = ρ L A = 0 . 431 × 9 . 25 × 10 - 3 10 - 6 R = 4   kΩ