Four capacitors marked with capacitances and breakdown voltages are connected as shown in the figure. The…

Four capacitors marked with capacitances and breakdown voltages are connected as shown in the figure. The maximum emf of the source, so that no capacitor breaks down is
  1. 10.5 kV
  2. 5.25 kV
  3. 2.25 kV
  4. 1.25 kV

Solution


Resultant capacitance of series combination 1 , $ \begin{aligned} & =\frac{1}{5}+\frac{1}{4}=\frac{9}{20} \\ C_{\mathrm{eq}_1} & =\frac{20}{9}=2.25 \mu \mathrm{F} \end{aligned} $ Resultant capacitance of series combination 2, $ \begin{aligned} & =\frac{1}{3}+\frac{1}{2}=\frac{5}{6} \\ C_{\mathrm{eq}_2} & =\frac{6}{5}=1 \cdot 2 \mu F \end{aligned} $ So, charge on upper branch is $=\frac{20}{9} \mathrm{~V}$ and charge on lower branch is $\frac{6}{5} \mathrm{~V}$.
So, smallest value is 2.25 kV

Asked in: AP EAMCET 2018 (23 Apr Shift 1)

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