A silicon wafer originally containing 1 P atom for every 10 million Si atoms is treated to produce a surface concentration of 400 P atoms per 10 million silicon atoms. Calculate the absolute value of the concentration gradient in atomic percent/cm and atoms/m^3/m. Silicon is diamond cubic with lattice parameter 5.4307 Angstroms.

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

An air compression refrigeration system is to have an air pressure of 100 psia in the brine tank and an allowable air temperature increase of 60°f for standard vapor compression cycle temperatures of 77 f entering the expansion cylinder and 14 f entering the compression cylinder, calculate the coefficient of performance a. 2.5 b 3.3 c. 4.0 d. 5.0

Find the minimum film thickness for a journal bearing with the data below. shaft diameter, d-50 mm, clearance ratio, cdratio? 0.001, shaft speed, n 2000 rpm; bearing length. i 200 mm; eccentricity ration, ? -0.55. ( note, cdratio-ca/d) the minimum film thickness is um