Chapter 5, Problem 5.3P

It is desired to bring about a certain change in the state of a system by performing work on the system under adiabatic conditions. (GATE-1998-2.17) (a) The amount of work needed is path-dependent (b) Work alone cannot bring about such a change of state (c) The amount of work needed is independent of path (d) More information is needed to conclude anything about the path dependence or otherwise the work needed

Calculate the change in internal energy of system under below cases: (1) Heat added to system = 600 J, Work done by system = 200 J (2) Heat rejected by system = 300 J, Work done on system = 100 J (3) Heat added to system = 700 J, Work done by system = 500 J

Refrigerators to preserve perishable foods have long been one of the essential appliances in a household. The refrigeration system of the household refrigerator is basically based on the vapor-compression refrigeration cycle, as shown in Figure Q2.1. Among the important components of the vapor-compressions refrigeration cycle are a throttling valve (A) and a compressor (B). In this refrigeration system, tetrafluoroethane (R-134a) is used as the refrigerant. Condenser W B A Evaporator Figure Q2.1: Basic components of a refrigeration system. (a) If the refrigerant enters A as a saturated liquid at 1100 kPa and leaves at 120 kPa, (i) Estimate the quality of the refrigerant at the exit of A. (ii) Calculate the temperature drop during the process. (iii)With appropriate assumptions, prove that the conservation of energy for A as follows the equation below, h= h2 (b) If the refrigerant enters B as a saturated vapor at 120 kPa with flow rate of 1.5 m³/min and leaves at 1100 kPa, (i) Calculate…