For pure GaAs at300 K, the concentration of electrons in the conduction band is equal to that of holes in the valence band (= 2 x 10⁶/cm³). Now we introduce selenium (Se) impurities at a concentration of 1 x 10¹⁶/cm³ into GaAs. Se is a group VI element sitting on As sites. Assume that all dopants are ionized and e = 1.6 x 10⁻¹⁹ C.
(a) What is the conductivity type (n or p)?
(b) Calculate the electron and hole concentrations.

Two flowing streams of argon gas are adiabatically mixed to form a single flow/stream. one stream is 1.5 kg/s at 400 kpa and 200 c while the second stream is 2kg/s at 500 kpa and 100 ? . it is stated that the exit state of the mixed single flow of argon gas is 150 c and 300 kpa. assuming there is no work output or input during the mixing process, does this process violate either the first or the second law or both? explain and state all your assumptions.

What precautions should you take to prevent injuries when dealing with heavy loads?

Aplate clutch has a single pair of mating friction surfaces 250-mm od by 175-mm id. the mean value of the coefficient of friction is 0.30, and the actuating force is 4 kn. a) find the maximum pressure and the torque capacity using the uniform-wear model. b) find the maximum pressure and the torque capacity using the uniform-pressure model.