5. water enters a 2.5 cm internal diameter thin copper tube of a heat exchanger at 30C at a rate of 0.3kg/s ans is heated by steam condensing outside at 120 c. if the average heat transfer coefficient is 800 w/m2k, determine the length of the tube required in order to heat the water to 100C

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Determine whether or not it is possible to compress air adiabatically from k to 140 kpa and 400 k. what is the entropy change during this process?

Burgers vector is generally parallel to the dislocation line. a)-true b)-false