A capacitor with capacitance 5 μF is charged to 5μC. If the plates are pulled apart to reduce the capacitance to 2μF, how much work is done?
(1) 3.75 x 10⁻⁶ J
(2) 6.25 × 10⁻⁶ J
(3) 2.55 × 10⁻⁶ J
(4) 2.16 × 10⁻⁶ J