What happens to the steam in a condensing turbine?

In a condensing turbine, steam expands and does work on the turbine blades, which causes the steam to lose energy and cool down as it exhausts. The correct choice describes that after performing work, the steam exhausts in a partially condensed state. This means that some of the steam transforms into water droplets while the remaining steam exists as vapor, indicating that the process involves cooling and phase change but does not entirely convert to liquid.

This is a key feature of condensing turbines, as they operate by extracting not only energy from steam but also facilitate its transition towards recondensation, which is important for maintaining efficient cycles in steam power plants. The ability of the exhaust steam to contain both vapor and liquid phases maximizes efficiency in recovery systems.

Other options do not accurately capture this nuance; for example, suggesting that steam is reused without condensation overlooks the need for a phase change to enable effective energy extraction, while stating that it is discharged as vapor would imply no cooling has taken place, failing to recognize the characteristic operation of a condensing turbine.