A. Determine the built-in potential barrier Vbi in a silicon pn junction for
(i) Nd = Na = 5 × 1015 cm−3 ;
(ii) Nd = 5 × 1017 cm−3 and Na = 1015 cm−3 ;
(iii) Na = Nd = 1018 cm−3 .

(b) Repeat part (a) for GaAs.

Amass of 1.5 kg of air at 120 kpa and 24°c is contained in a gas-tight, frictionless piston-cylinder device. the air is now compressed to a final pressure of 720 kpa. during the process, heat is transferred from the air such that the temperature inside the cylinder remains constant. calculate the boundary work input during this process.

Avolume of 2.65 m3 of air in a rigid, insulated container fitted with a paddle wheel is initially at 264 k, 5.6 bar. the air receives 432 kj by work from the paddle wheel. assuming the ideal gas model with cv = 0.71 kj/kg • k, determine for the air the amount of entropy produced, in kj/k

With increases in magnification, which of the following occur? a. the field of view decreases. b. the ambient illumination decreases. c. the larger parts can be measured. d. the eyepiece must be raised.