Answer to Question #159160 in Electric Circuits for Onel

Question

A horizontal portion of a circuit contains 3 aligned points A, B and C. A 2.0uF and a 3.0uF capacitor are shunted between A and B, and there is a 5uF capacitor between B and C. Above this alignment is a series connection of a 100V battery and a switch S1 connected to A and C. Below the alignment is a 10 ohm resistor and a switch S2 connected to A and C. The switches are initially opened.
(i) Draw a diagram of the circuit
(ii) If S1 is opened and S2 closed, how much charge flows through the 10 ohm resistor?
(iii) If another resistor is connected in series to the 10 ohm resistor, will the flow of charge be affected? Explain.

Answer 1

Explanations & Calculations

1)

2)

• Since the $S_1$ switch has not been closed there is neither a connected circuit nor any way for the capacitors to get charged.
• Closing only $S_2$ allows any stored charge to flow though but in this case no charge is flowing as there is no any stored charge.

3)

• It does nothing in this case but when another resistor is connected in series, the effective circuit resistance increases, thereby decreasing the flowing current.
• It will take more time to discharge the capacitors which were given the same charge as with the $\small 10 \Omega$ only.
• It is understood by the current equation of RL circuits $\small i=i_0e^{-\frac{t}{RC}}$ : $\small R\uparrow\implies t\downarrow$