Question

On doping germanium with donor atoms density of ${10}^{17}{cm}^{-3}$ its conductivity in mho/cm will be
(Given ${\mu }_e=3800{cm}^2/V-s$ and $n_i=2.5\times {10}^{13}{cm}^{-13}$)

• A. $30.4$
• B. $60.8$
• C. $91.2$
• D. $121.6$

Answer 1

The correct option is B $60.8$

The conductivity of the doped germanium can be written as-

$\sigma =n_e.{\mu }_e.q_e$

$\sigma =\left({10}^{17}c{m}^{-3}\right).\left(3800c{m}^2{V}^{-1}{s}^{-1}\right).\left(1.6\times {10}^{-19}C\right)$

$\sigma =60.8\mho .c{m}^{-1}$

Option (B) is correct.