An insulated piston-cylinder device contains 5 L of saturated liquid water at a constant P of 175 kPa. Water is stirred by a paddle wheel while a current of 8 A flows for 45 min through a resistor placed in the water. If one-half of the liquid is evaporated during this constant-pressure process and the paddle- wheel work amounts to 400 kJ, determine the voltage of the source. Draw the Pv diagram. P= const. -> W sh W.