An instrument that identifies humidity is known as?

• A. Psychrometer
• B. Hygrometer
• C. Thermometer
• D. Hydrometer

Answer: (B)

A hygrometer is an instrument specifically designed to measure the amount of moisture in the air, or humidity. It provides vital information about atmospheric conditions, which can be particularly important in various settings such as meteorology, climatology, and even in certain industrial processes where humidity control is crucial. Different types of hygrometers exist, including analog and digital forms, but their primary function remains the same—quantifying humidity levels.

In contrast, a psychrometer is used for a similar purpose but typically consists of two thermometers—one dry and one wet—and measures humidity based on the difference in temperature readings between the two. This makes it a specific type of hygrometer, but not the general term. A thermometer measures temperature rather than humidity, and a hydrometer measures the specific gravity or density of liquids, which is unrelated to air humidity. Therefore, the correct choice identifies the general instrument for measuring humidity directly.