(a) Consider a germanium semiconductor at T 300 K. Calculate the thermal equilibrium electron and hole concentrations for (i) Nd 2 1015 cm3, Na 0, and (ii) Na 1016 cm3, Nd 7 1015 cm3. (b) Repeat part (a) for GaAs. (c) For the case of GaAs in part (b), the minority carrier concentrations are on the order of 103 cm3. What does this result mean physically

The filament of an incandescent lamp has a temperature of 2000k. calculate the fraction of radiation emitted in the visible light band if the filament is approximated as blackbody

Air inially occupying a volume of 1 m2 at 100 kpa, 27 c undergoes three internally reversible processes in series. process 1-2 compression to 500 kpa during which pv constant process 2-3 adiabatic expanslon to 100 kpa process 3-1: constant-pressure expansion to 100 kpa (a) calculate the change of entropy for each of the three processes. (b) calculate the heat and work involved in each process. (c) is this cycle a power cycle or refrigeration cycle?

A21-tooth spur pinion mates with a 28-tooth gear. the diametral pitch is 3 teeth/in and the pressure angle is 20°, find the following values: the addendum, dedendum, circular pitch, tooth thickness, and base circle diameters.