Determine (a) the vacancy fraction for a metal at a temperature of 471 deg c if the energy of vacancy formation is 0.27 ev/atom and (b) the vacancy density (vacancies per cu. m) if the density and molecular weight are 52.4 g/cc and 1388.6 g/mole, respectively.

A2-m rigid tank initially contains saturated water vapor at 100 kpa. the tank is connected to a supply line through a valve. steam is flowing in the supply line at 600 kpa and 300 c. the valve is opened, and steam is allowed to enter the tank until the pressure in the tank reaches the line pressure, at which point the valve is closed. a thermometer placed in the tank indicates that the temperature at the final state is 200°c. determine (a) the mass of steam that has entered the tank (b) the amount of heat transfer.

An electric kettle is made out of stainless steel, weighs two pounds (when empty) and is equipped with a heating element that consumes 2 kw of electricity. assuming that the water and the kettle are at the same uniform temperature at any moment of time, calculate the shortest possible time to bring 2 quarts of water from room temperature to the onset of boiling

Areheat rankine cycle operates with water as the working fluid. steam enters the first turbine at 8 mpa and 450°c and exits at 0.8 mpa. it is then reheated to 400°c before entering the second turbine, where it exits at 10 kpa. if the amount of work into the pump is 8.04 kj/kg and the net work per cycle produced is 1410.25 kj/kg, determine the thermal efficiency of the cycle.