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As shown in the figure, in steady state, the charge stored in the capacitor is _____ $$\times 10^{-6}$$ C.
Correct Answer: 10
We need to find the charge stored in the capacitor under steady-state conditions for the given circuit.
In a DC circuit, once a capacitor is fully charged and reaches a steady state, it acts as an open circuit (infinite resistance). This means:
Using the values given in the circuit diagram
The total current flowing through the main loop is:
$$I = \frac{E}{R + r} = \frac{10}{100 + 10} = \frac{10}{110} = \frac{1}{11}\text{ A}$$
Since no current flows through the branch with $$R' = 200\ \Omega$$, there is no potential drop across it ($$V_{R'} = 0$$). Therefore, the potential difference ($$V_C$$) across the capacitor plates is exactly equal to the potential difference across the parallel resistor ($$R$$):
$$V_C = I \times R$$
$$V_C = \frac{1}{11}\text{ A} \times 100\ \Omega = \frac{100}{11}\text{ V}$$
The capacitance value given is $$C = 1.1\ \mu\text{F} = 1.1 \times 10^{-6}\text{ F}$$. Using the formula for charge stored in a capacitor ($$Q = C \times V_C$$):
$$Q = 1.1 \times 10^{-6}\text{ F} \times \frac{100}{11}\text{ V}$$
We can rewrite $$1.1$$ as $$\frac{11}{10}$$ to simplify the expression easily:
$$Q = \left(\frac{11}{10} \times 10^{-6}\right) \times \frac{100}{11}$$
$$Q = \frac{100}{10} \times 10^{-6}\text{ C} = 10 \times 10^{-6}\text{ C}$$
The charge stored in the capacitor in steady state is 10 $$\times 10^{-6}\text{ C}$$.
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