In which application would a rotameter typically be used?

A rotameter is primarily used for measuring the flow rate of liquids and gases in a wide range of applications. Its design, which consists of a tapered tube and a float that rises or falls based on the flow rate, makes it suitable for specific conditions.

When considering the use of a rotameter, it is crucial to recognize that these instruments can be constructed from materials that withstand corrosive substances, allowing them to function effectively in applications involving corrosive liquids. This capability makes option B the most appropriate application for a rotameter, as it highlights the instrument's versatility in handling various fluid types while maintaining accuracy.

In contrast, applications like high-pressure gas measurement, low-temperature gas measurement, and solid particulate flow may require different types of flow measurement devices to ensure accurate and reliable readings. For instance, high-pressure gas applications often utilize devices specifically designed for such conditions, which may pose limitations for standard rotameters. Similarly, measuring solid particulate flow presents challenges that rotameters are not equipped to handle effectively, as they are designed for continuous flow through a liquid or gas rather than solids.