Q. 46 The non-dimensional fluid temperature profile near the surface of a convectively cooled flat plate is given by TW-T = a+b+c (2), where y is measured perpendicular to the plate, L is the plate length, and a, b and c are arbitrary constants. Tw and T are wall and ambient temperatures, respectively. If the thermal conductivity of the fluid is k and the wall heat flux is q", the Nusselt number Nu = is equal to (A) a -T (C) 2c (D) (b+2c) Q. 47 In an air-standard Otto cycle, air is supplied at 0.1 MPa and 308 K. The ratio of the specific heats (r) and the specific gas constant (R) of air are 1.4 and 288.8 J/ kg.K, respectively. If the compression ratio is 8 and the maximum temperature in the cycle is 2660 K, the heat (in kJ/kg) supplied to the engine is Q. 48 A reversible heat engine receives 2 kJ of heat from a reservoir at 1000 K and a certain amount of heat from a reservoir at 800 K. It rejects 1 kJ of heat to a reservoir at 400 K. The net work output (in kJ) of the cycle is