1. The problem statement, all variables and given/known data in Intrinsic GaAs,electron and hole mobility are 0.85 and 0.04 meter square/volt-sec and corresponding effective mass are 0.068m and 0.5m, where m=9.11*10^(-31)kg. band gap energy is 1.43 eV at 300K. ---calculate intrinsic carrier concentration(!) and Conductivity. 2. Relevant equations the eqs I know related with mobility are; mu=v/F=e*tau/m(eff) conductivity=e(n*mu[n]+p*mu[p]). mu=mobility e=charge of carrier(say electron) 3. The attempt at a solution but what are the formulae to relate between mobility,carrier concentration using effective mass? if carrier concentration is calculated, then conductivity=e(n*mu[n]+p*mu[p]). please help me.anyone.