Atotal of 10 rectangular aluminum fins (k 5203 w/m·k) are placed on the outside flat surface of anelectronic device. each fin is 100 mm wide, 20 mm highand 4 mm thick. the fins are located parallel to each otherat a center-to-center distance of 8 mm. the temperature atthe outside surface of the electronic device is 60°c. the airis at 20°c, and the heat transfer coefficient is 100 w/m2.k. determine(a) the rate of heat loss from the electronic device to the surrounding air and (b) the fin effectiveness.

When using the ohmmeter function of a digital multimeter, the leads are placed in what position relative to the component being tested? a. parallel b. control c. series d. line

Aflywheel accelerates for 5 seconds at 2 rad/s2 from a speed of 20 rpm. determine the total number of revolutions of the flywheel during the period of its acceleration. a.5.65 b.8.43 c. 723 d.6.86

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?