(a) The applied electric field in p-type silicon is \(E=10 \mathrm{~V} / \mathrm{cm}\). The semiconductor conductivity is \(\sigma=1.5(\Omega-\mathrm{cm})^{-1}\) and the cross-sectional area is \(A=10^{-5} \mathrm{~cm}^{2}\). Determine the drift current.

(b) The cross-sectional area of a semiconductor is \(A=2 \times 10^{-4} \mathrm{~cm}^{2}\) and the resistivity is \(ho=0.4\) \((\Omega-\mathrm{cm})\). If the drift current is \(I=1.2 \mathrm{~mA}\), what applied electric field must be applied?