You are given six identical capacitors of capacitance C that can each withstand a potential difference of 12V across them. These must be interconnected in such a way as to fabricate a capacitor capable of working with a potential difference of 36V across it. What is the maximum effective capacitance that can be achieved?

C/3
3C/2
C/6
2C/3
3C

1 answer

To achieve a capacitor configuration that can handle a potential difference of 36V using 6 identical capacitors of capacitance C (each can withstand up to 12V), we need to understand how to arrange these capacitors.

  1. Maximum Voltage Handling: Since each capacitor can handle a maximum of 12V, in order to make a capacitor bank capable of withstanding 36V, we need to connect them in series to increase the voltage rating.

    To achieve a combined voltage of 36V, we can place 3 capacitors in series. This way, the maximum voltage across a series arrangement of 3 capacitors will be: \[ V_{\text{total}} = 12V + 12V + 12V = 36V \]

  2. Finding Effective Capacitance in Series: The capacitance of capacitors in series is calculated using the formula: \[ \frac{1}{C_{\text{series}}} = \frac{1}{C_1} + \frac{1}{C_2} + \frac{1}{C_3} \] Since all three capacitors have the same capacitance (C), the total capacitance becomes: \[ \frac{1}{C_{\text{series}}} = \frac{1}{C} + \frac{1}{C} + \frac{1}{C} = \frac{3}{C} \] Therefore, \[ C_{\text{series}} = \frac{C}{3} \]

  3. Remaining Capacitors in Parallel: We still have 3 capacitors left, which can be connected in parallel. The combined capacitance of capacitors in parallel is simply the sum of their capacitances. Therefore, if we connect 3 capacitors (each with capacitance C) in parallel, we have: \[ C_{\text{parallel}} = C + C + C = 3C \]

  4. Effective Capacitance of the Combined Configuration: Now, we combine the series arrangement (with 3 capacitors) and the parallel arrangement (with another 3 capacitors). The total effective capacitance in such a configuration becomes the parallel combination of the series and parallel arrangements. Since the series arrangement with three capacitors gives us \( \frac{C}{3} \), and the parallel arrangement with three capacitors gives \( 3C \), we have them in parallel: \[ C_{\text{total}} = C_{\text{series}} + C_{\text{parallel}} = \frac{C}{3} + 3C \]

    First, we convert \(3C\) into a fraction over the same denominator: \[ 3C = \frac{9C}{3} \]

    Thus, \[ C_{\text{total}} = \frac{C}{3} + \frac{9C}{3} = \frac{10C}{3} \]

  5. Conclusion: The maximum effective capacitance that can be achieved with the given configuration that can withstand a voltage of 36V, using the maximum voltage capacity of the capacitors, is \[ \frac{10C}{3}. \] This value \( \frac{10C}{3} \) is not given in the options, thus it could be that further breakdown or analysis is required, or it could differ based on configurations mentioned. However, given constraints, connecting capacitors in series and maintaining parallel connections ultimately conclude effective capacitance estimated to highest value \(3C\), if we consider the resultant corrective approach of inter-repeating configurations.

From options considering effective bounds may end at \( \boxed{3C} \).