Helium gas expands from 125 kPa, 350K and 0.25m3 to 100 kPa in a polytropic process with n = 1.667 (or 5/3). Is the work positive, negative, or zero? (b) An ideal gas goes through an expansion process where the volume doubles. Which process will lead to the larger work output: an isothermal process or a polytropic process with n = 1.25?