A volt meter measures the voltage across which parts of the apparatus?

A voltmeter is specifically designed to measure the electrical potential difference, or voltage, across two points in an electrical circuit. When measuring voltage, it is essential to connect the voltmeter across the terminals of the component whose voltage you wish to measure.

In the context of the question, measuring the voltage across battery terminals is particularly significant because it provides essential information about the state of charge and overall condition of the battery. By placing the voltmeter across the battery terminals, you can determine whether the battery is functioning properly and if it is delivering the required voltage necessary for the operation of the vehicle or apparatus.

Measuring voltage across fuse terminals, control panels, or ground connections might not provide a clear representation of the battery’s condition or the voltage required by various components. These measurements could indicate voltage drops or potential issues due to other factors but do not directly evaluate the battery's performance or health. Thus, the most relevant and straightforward application of a voltmeter in this case is at the battery terminals.