A simple device that uses the laws of electrostatics to detect small electric charges is a(n) ?

• A. Voltmeter
• B. Electroscope
• C. Ammeter
• D. Galvanometer

Answer: (B)

Detecting small electric charges with a device that uses electrostatic forces. An electroscope responds to static charges by making its two metal leaves separate: when a charged object touches or is near the top, charges move into the leaves, giving them the same sign so they repel each other. The repulsion causes the leaves to diverge, and the greater the charge, the larger the separation. This makes it a simple, direct detector of small charges without needing a closed electrical circuit. In contrast, voltmeters measure potential difference in a circuit, ammeters measure current, and galvanometers detect small currents; they rely on current flow or circuit conditions rather than sensing isolated static charge.