A charged capacitor stores 10 C at 40 V.. Its stored energy is:
Correct answer: D. 200 J
- A. 400 J
- B. 4 J
- C. 0.2 J
- D. 200 J
Explanation
The energy stored in a capacitor can be calculated using the formula U = 0.5 * Q * V, where U is the energy, Q is the charge, and V is the voltage. Given Q = 10 C and V = 40 V, the calculation is U = 0.5 * 10 C * 40 V = 200 J. Therefore, the correct answer is 200 J. The other options (400 J, 4 J, and 0.2 J) are incorrect because they do not follow the correct application of the formula.
This question appeared on the ETEA MDCAT 2016 paper, which you can sit online with every answer explained.
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About Capacitors
Capacitors store electric charge and energy in an electric field between conductors. Work includes capacitance, the relation Q = CV, dielectric materials, charging and discharging, energy formulas, and combinations of capacitors in series and parallel. Electric potential difference is needed to understand why charge and stored energy change.
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