Afully charged iphone battery stores about 5.45 watt-hours of energy. a company has developed a charging source for cell phone batteries that is mainly solar panels with active dimensions of 0.3 m x 0.3 m. how long will it take for this charging source to take a cell phone battery from completely drained to fully charged? assume the average solar radiance is 150 w/m2 and the conversion efficiency of the solar panels is 15%.

Acompressor receives the shaft work to decrease the pressure of the fluid. a)- true b)- false

For the closed feedwater heater below, feedwater enters state 3 at a pressure of 2000 psia and temperature of 420 °f at a rate of ix10 ibhr. the feedwat extracted steam enters state 1 at a pressure of 1000 psia and enthalpy of 1500 btu/lbm. the extracted er leaves at an enthalpy of 528.7 btu/lbm steam leaves as a saturated liquid. (16) a) determine the mass flow rate of the extraction steam used to heat the feedwater (10) b) determine the terminal temperature difference of the closed feedwater heater

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