Question
  1. A parallel plate capacitor $(C_1)$ having charge $Q$ is connected, to an identical uncharged capacitor $C_2$ in series. What would be the charge accumulated on the capacitor $C_2?$
  2. Three identical capacitors each of capacitance $3mF$ are connected, in tern, in series and in parallel combination to the common source of $V$ volt. Find out the ratio of the energies stored in two configurations.

Answer

  1. Zero.
  2. We have $\text{C}_{series} = \frac{3\mu\text{F}}{3} =1 \mu\text{F}$
Also, $\text{C}_{parallel} =( 3 + 3 +3 ) =9 \mu\text{F}$
Energy stored $ = \frac{1}{2}\text{CV}^{2}$
$\therefore$Energy in series combination $ =\frac{1}{2}1 \times10^{-6}\times\text{V}^{2}$
Energy in parallel combination $ =\frac{1}{2}9 \times10^{-6}\times\text{V}^{2}$
$\therefore$ Ratio $= 1:9.$

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