A piston-cylinder device initially contains 0.5m3 of nitrogen gas at 400 kPa and 27 °C. Anelectric heater within the device is turned on and is allowed to pass a current of 2 A for 5min from a 120V source. Nitrogen expands at constant pressure, and a heat loss of 2800 Joccurs during the process. Determine the final temperature of nitrogen. Assume nitrogen to be an ideal gas with M = 28 g/mol and cp=1.039 kJ/kg. K

Fluids at rest possess no flow energy. a)- true b)- false

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

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.