What is the purpose of an electroscope?

An electroscope is primarily used to detect electric charge. When an object with an electric charge is brought close to or comes into contact with the electroscope, it causes the leaves of the device to either separate or collapse, depending on the nature of the charge. This movement indicates the presence of an electric charge, allowing the user to infer whether the object is positively or negatively charged.

The other options describe functions that an electroscope does not perform. For instance, measuring voltage requires a different instrument called a voltmeter, while storing charge would necessitate a capacitor. Generating electricity is typically the role of a generator, not an electroscope. The primary function of the electroscope remains its ability to detect charges through observable physical changes.