What is superheated steam?

Superheated steam is steam that has been heated to a temperature higher than the saturation temperature corresponding to its pressure. This means that it is no longer in equilibrium with liquid water at the same pressure and is in a distinct state apart from the mixture of liquid and vapor. The heating beyond the saturation point increases the thermal energy of the steam without changing its pressure. This property is significant in various steam applications, as superheated steam has higher energy content and can be used to drive turbines more efficiently because it reduces the risk of water droplets forming, which can cause damage to turbine blades.

The other choices refer to different concepts that do not accurately define superheated steam. The first choice describes saturated steam, which exists at the temperature corresponding to its pressure. The third option simply states that the steam has not been heated, which does not apply to superheated steam, and the fourth option describes a mixture of steam and water, which would not qualify as superheated steam.