Which of the following devices is used to measure electric charge directly in a circuit?

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

Answer: (C)

Verified step by step guidance

1. Understand the function of each device listed: a Voltmeter measures electric potential difference (voltage), an Ammeter measures electric current, a Resistor opposes current flow, and an Electroscope detects electric charge.
2. Recall that measuring electric charge directly in a circuit requires a device sensitive to the presence and amount of charge, not voltage or current.
3. Recognize that an Electroscope is a device that can detect and measure electric charge by the movement or divergence of its leaves due to electrostatic forces.
4. Note that Voltmeters and Ammeters are designed to measure voltage and current respectively, not charge, and Resistors are passive components, not measuring devices.
5. Conclude that the Electroscope is the correct device used to measure electric charge directly in a circuit.