Corrections for local acceleration of gravity must be applied to which type of measurements?

The need to apply corrections for local acceleration of gravity primarily relates to pressure measurements conducted using piston gages. A piston gage utilizes a piston and cylinder arrangement, where the pressure is derived based on the balance of the force exerted by the fluid and the weight of the piston. Since the weight of the piston is influenced by the local gravitational acceleration, variations in gravity due to geographic location or altitude necessitate that corrections be made to ensure accuracy. If the local gravity differs from the standard value assumed in calculations, the pressure readings could result in systematic errors.

In contrast, thermometer readings are not affected by variations in gravity because temperatures are measured based on the expansion or contraction of a fluid that is independent of gravitational force. Digital multimeter readings, which measure electrical quantities, do not require gravity corrections as they are based purely on electrical properties. Similarly, while pressure measurements may seem relevant, if they are not directly related to piston gages, gravity corrections would not apply universally across all pressure measurement devices.

Therefore, the context of measurements using piston gages makes it essential to account for local gravitational acceleration, thereby making this the correct choice for the application of gravity corrections.