When two flat plate conductors are arranged in such a way that they possess equal and opposite charges seperated by a dielectric, they form a/an

Analyze the question: Two flat plate conductors carry equal and opposite charges and are separated by an insulating material (a dielectric). We need to name this arrangement.

Explain the concept: A capacitor is a device that stores electric charge and energy. It consists of two conductors (often parallel plates) separated by an insulator called a dielectric. One plate holds +Q and the other −Q.

Key formulas:

• Capacitance: C = Q/V
• Parallel-plate capacitor: C = εA/d, where A is the plate area, d is the separation, and ε is the permittivity of the dielectric
• Energy stored: W = ½CV²

Check each option:

• A. Electroscope: detects the presence of charge using the deflection of a leaf. It is not made of two oppositely charged plates with a dielectric.
• B. Electrophorus: produces charge by induction using an insulating disc and a metal plate. It does not store equal and opposite charges on two plates separated by a dielectric.
• C. Capacitor: matches the description exactly.
• D. Cell: produces an e.m.f. through chemical reactions. It does not fit this description.

Answer: The arrangement is a capacitor, which is option C.

Exam tip: If you see "two conductors + dielectric + equal and opposite charges," think capacitor. Remember "Capacitor = Condenser = Charge storage."