Exam-style question
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If the potential difference across a capacitor is doubled, what happens to the energy stored in the capacitor?.
- A.It doubles
- B.It triples
- C.It quadruples
- D.It remains the same
Model answer
What a good answer should say
- It quadruples
Explanation
Why this works
The energy stored in a capacitor is given by E = 0.5 x C x V^2. If the potential difference V is doubled, the energy becomes E = 0.5 x C x (2V)^2 = 0.5 x C x 4V^2, which shows that the energy stored quadruples when the potential difference is doubled.
Common mistake
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