A capacitor of 5 μF is connected to a 20 V battery. The energy stored in the capacitor is:
Correct answer: B. 2 × 10⁻³ J
- A. 10⁻³ J
- B. 2 × 10⁻³ J
- C. 10⁻⁴ J
- D. 5 × 10⁻⁴ J
Explanation
Energy stored in a capacitor is U = (1/2)CV². With C = 5 × 10⁻⁶ F and V = 20 V, U = (1/2)(5 × 10⁻⁶)(20)² = 2 × 10⁻³ J.
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Electrostatics describes forces between charges through Coulomb's law, electric fields and field intensity, then uses electric potential to measure energy per unit charge. Capacitors store charge and electrical energy, with capacitance depending on geometry and dielectric material, not simply on the amount of charge present.
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