Electrostatic Potential and Capacitance - Result Question 37

39. Three capacitors each of capacity $4 \mu F$ are to be connected in such a way that the effective capacitance is $6 \mu F$. This can be done by [2003]

(a) connecting two in parallel and one in series

(b) connecting all of them in series

(c) connecting them in parallel

(d) connecting two in series and one in parallel

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Answer:

Correct Answer: 39. (d)

Solution:

  1. (d) For series, $C^{\prime}=\frac{C_1 \times C_2}{C_1+C_2}=\frac{4 \times 4}{4+4}=2 \mu F$

For parallel, $C _{eq}=C^{\prime}+C_3=2+4=6 \mu F$

If $C_P$ is the effective capacity when $n$ identical capacitors are connected in parallel and $C_s$ is their effective capacity when connected in series then $\frac{C_p}{C_s}=n^{2}$