A saturated liquid water enters a boiler at P1 = 1.1 MPa and x1 = 0. Heat is transferred to the steam from a reservoir at temperature Th. The steam then enters a perfectly insulated turbine, where 500 kJ per kg of steam is extracted as work. The steam exits the turbine as a saturated vapor at P2 = 100 kPa and x2 = 1. Determine the minimum value of Th possible for this process, according to the 2nd Law of Thermodynamics.