What is the conductivity of a semiconductor sample having electron concentration of $5 \times 10^{18} m^{−3}$, hole concentration of $5 \times 10^{19} m^{-3}$, electron mobility of $2.0\; m^2V^{-1} s^{-1}$ and hole mobility of $0.01 m^2V^{-1}s^{-1}$? (Take charge of electron as $1.6 \times 10^{-19}C$)

Question

$\begin{array}{1 1}(1)\;1.68 (Ω - m)^{−1}\\ (2)\; 1.83 (Ω - m)^{−1}\\ (3)\; 0.59 (Ω - m)^{−1}\\ (4)\; 1.20 (Ω - m)^{−1} \end{array}$