Question

Seven capacitors each of capacitance 2 mF are to be connected to obtain a capacitance of 10/11 mF. Which of the following combination is possible?

5 in parallel, 2 in series

4 in parallel, 3 in series

3 in parallel, 4 in series

2 in parallel, 5 in series

Pls explain the ans also.

Answer 1

Answer:

We will connect the 5 capacitor in parallel and 2 in series.

(a) is correct option.

Explanation:

Given that,

Capacitance = 2 mF

We need to find the combination in this options

We have to combine the 5 capacitors in parallel and 2 capacitors in series.

$\dfrac{1}{C_{effe}}=\dfrac{1}{C_{1}+C_{2}+C_{3}+C_{4}+C_{5}}+\dfrac{1}{C_{6}}+\dfrac{1}{C_{7}}$

Put the value into the formula

$\dfrac{1}{C_{effe}}=\dfrac{1}{2+2+2+2+2}+\dfrac{1}{2}+\dfrac{1}{2}$

$\dfrac{1}{C_{effe}}=\dfrac{1}{10}+\dfrac{1}{2}+\dfrac{1}{2}$

$\dfrac{1}{C_{effe}}=\dfrac{11}{10}$

$C_{effe}=\dfrac{10}{11}\ mF$

Hence, We will connect the 5 capacitor in parallel and 2 in series.