$0.36 m^2/V-sec$ and$0.17m^2/V-sec$ respectively. If electron and holes densities are equal and it is $2.5 ×10^{13}/cm^3$, calculate its conductivity.

Data :- $μ_e = 0.36 m^2/V-sec \hspace{1cm} μ_h = 0.17m^2/V-sec \hspace{1cm} T =300°K$

$n_i=2.5×10^{13}/cm^3 = 2.5×10^{19} m^3$

Formula :- $σ=n(μ_e- μ_h ).e$

Calculations :- $σ=2.5×10^{19} (0.36+0.17)×1.6×10^{-19}$

=2.12 mho/metre

Answer :- σ= conductivity = 2.12 mho/metre.