Energy stored by a capacitor Quiz
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5 questions, one answer each
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1. A 1000 µF capacitor is charged to 6.0 V. What energy does it store?
- A. 3.6 × 10⁻² J
- B. 6.0 × 10⁻³ J
- C. 1.8 × 10⁻² J
- D. 1.7 × 10⁵ J
2. The p.d. across a capacitor is trebled. By what factor does the stored energy increase?
- A. 3
- B. 6
- C. 9
- D. 27
3. A capacitor stores 4.0 mC at 25 V. What energy does it store?
- A. 1.0 × 10⁻¹ J
- B. 1.6 × 10⁻⁴ J
- C. 6.3 × 10³ J
- D. 5.0 × 10⁻² J
4. The Q–V graph of a capacitor has gradient 2.0 × 10⁻⁵ C V⁻¹. What is the energy stored when V = 50 V?
- A. 5.0 × 10⁻² J
- B. 2.5 × 10⁻² J
- C. 1.0 × 10⁻³ J
- D. 5.0 × 10⁻⁴ J
5. Which expression gives the energy stored in a capacitor in terms of Q and C?
- A. Q²/2C
- B. QC/2
- C. 2Q²C
- D. C/2Q²