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    Question

    A dielectric is pulled out of a charged capacitor

    (battery disconnected). The potential difference:
    A Increases Correct Answer Incorrect Answer
    B Decreases Correct Answer Incorrect Answer
    C Stays the same Correct Answer Incorrect Answer
    D Becomes zero Correct Answer Incorrect Answer

    Solution

    When a dielectric is pulled out of a charged capacitor that is disconnected from a battery, the following occurs: 1.     Charge (Q) remains constant: Since the capacitor is disconnected from the battery, it's an isolated system. No charge can flow on or off the plates, so the total charge stored on the capacitor plates remains the same.

    2.     Capacitance (C) decreases: The capacitance of a capacitor is directly proportional to the dielectric constant (κ) of the material between its plates (C ∝ κ). Air or vacuum has a dielectric constant of approximately 1, while any dielectric material has κ>1. When the dielectric is pulled out, κ effectively decreases to 1, causing the capacitance to decrease.

    3.     Potential difference (V) increases: The relationship between charge, capacitance, and potential difference is given by Q=CV. Since Q is constant and C decreases, for the product CV to remain constant (equal to Q), the potential difference V must increase. Therefore, the potential difference (A) Increases .

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