What device is used to indicate whether an object carries a positive or negative charge?

An electroscope is the correct device to indicate whether an object carries a positive or negative charge. This instrument operates based on the principles of electrostatics and allows observers to visually see the presence of electric charge. When a charged object is brought near the electroscope, it causes the leaves of the device (often made of lightweight metal) to diverge due to repulsion or attraction between the charges.

If a positively charged object is brought close to the electroscope, the electroscope will show a positive charge if the leaves diverge as the electrons in the electroscope move away from the positive charge. Conversely, if a negatively charged object is used, then the electroscope can also show a negative charge. Observers can determine the type of charge by the movement of the leaves and their relative positions.

In the context of other devices, grounding refers to the process of transferring charge to the Earth and does not indicate charge on an object. A load is related to a component that consumes electrical energy, while an oscilloscope is used to view and measure varying electrical signals and is not designed for detecting charge. Thus, the electroscope stands out as the specific tool meant for detecting and indicating whether an object possesses a positive or negative electric charge.