A manometer filled with oil or water is primarily used to measure what?

A manometer is an instrument that measures the pressure of liquids and gases by using a column of liquid, typically water or oil, to indicate pressure differences. It operates based on hydrostatic principles, where the height of the liquid column correlates to the pressure difference it is measuring.

When it comes to measuring air pressure, especially in applications like assessing the pressure drop across an air filter, a manometer is particularly effective. As air flows through a filter, the resistance it encounters changes the pressure before and after the filter, which can be accurately gauged using a manometer. The difference in the liquid levels in the manometer indicates how much pressure has dropped as the air passes through the filter, allowing for effective monitoring of the system’s performance.

Other choices relate to measurements that are not the primary function of a manometer. For example, measuring the water level in a tank typically involves a different type of instrument, and while temperature measurements can influence gas conditions, they aren’t provided by a manometer. Similarly, measuring gas flow rate usually requires flow meters designed specifically for that purpose, rather than a manometer, which does not directly measure flow but rather pressure levels.