Four wires meet at a junction. in two of the wires currents i1 = 1.67 a and i2 = 2.37 a enter the junction. in one of the wires current i3 = 6.85 a leaves the junction. find the current in the fourth wire and indicate its direction.

Arefrigerator uses r-134a as the working fluid and operates on the ideal vapor-compression refrigeration cycle except for the compression process. the refrigerant enters the evaporator at 120 kpa with a quality of 34 percent and leaves the compressor at 70°c. if the compressor consumes 450 w of power, determine (a) the mass flow rate of the refrigerant, (b) the condenser pressure, and (c) the cop of the refrigerator. (0.00644 kg/s, 800 kpa, 2.03)