2. What The relaxation time r between collisions of electrons in a certain material is \( 6.2 \times 10^{-} \) \( { }^{14} \mathrm{~s} \). If the number of free electrons \( \mathrm{n}=2.5 \times 10^{13} \), charge of an electron \( \mathrm{e}=1.6 \times 10^{-19} \mathrm{C} \) and mass of an electron \( \mathrm{m}_{\mathrm{e}}=9.11 \times 10^{-31} \mathrm{~kg} \). Find; -
i)Conductivity, ii) Resistivity, iii) Mobility