The amount of saturated water in a unit quantity of steam is indicated by which term?

The term that indicates the amount of saturated water in a unit quantity of steam is known as the dryness fraction. The dryness fraction is a crucial parameter in the study of steam and thermodynamics, quantifying the ratio of the mass of steam (vapor) to the total mass of the steam and water mixture. It ranges from 0 to 1, where a value of 0 indicates completely saturated water, while a value of 1 signifies completely dry steam. Understanding the dryness fraction is essential for assessing the quality of steam in various applications, as it helps in calculating the efficiency of steam systems and the appropriateness of steam for specific processes.

The other terms listed do not specifically measure the saturation of water in steam. For instance, partial pressure pertains to the pressure exerted by a single component of a gas mixture and is not suitable for measuring the water content in steam. The saturation index refers more to a ratio used in evaluating the state of a solution concerning its saturation level, while moisture index typically relates to the quantity of moisture present in a material, rather than specifically in steam. Thus, the dryness fraction is the most applicable and specific term in this context.