1. Estimate the electrical conductivity at 85°C of silicon that has been doped with 1020 m−3 of phosphorus atoms.
2. A hypothetical metal is known to have an electrical resistivity of 4 ×10−8 (Ω·m). A current of 30 A is passed through a specimen of this metal 25 mm thick. When a magnetic field of 0.75 tesla is simultaneously imposed in a direction perpendicular to that of the current, a Hall voltage of −1.26 ×10−7 V is measured. Compute the following:
(a) the electron mobility for this metal
(b) the number of free electrons per cubic meter.
