Consider a two-stage cascade refrigeration system operating between 0.1 MPa and 1 MPa. Each stage operates on the ideal cycle with R-134a as the working fluid. Heat rejection from the lower to the upper cycle occurs at 0.4 MPa. If the mass flow rate in the upper cycle is 0.1 kg/s, determine (a) the mass flow rate through the lower cycle and (b) the COP. (c) What-if Scenario: What would the COP be if the intermediate pressure were changed to 0.6 MPa?