Question 718: Electrostatics & Capacitance

Question

In the circuit shown below, the switch S is connected to position P for a long time so that the charge on the capacitor becomes q
1
$$\mu$$C. Then S is switched to position Q. After a long time, the charge on the capacitor is q
2
$$\mu$$C.
The magnitude of q
1
is ________________.

Accepted Answer

Switch connected to position P
$${V_A} - 1\,.\,{i_1} - 1 + 2 - 2{i_1} = {V_A}$$
$$3{i_1} = 1$$
$${i_1} = {1 \over 3}A$$
Now, $${V_A} - 1\,.\,{i_1} - 1 = {V_B}$$
$${V_A} - {V_B} = 1 + {i_1} = {4 \over 3}V$$
Potential drop across capacitor, $$\Delta V = {4 \over 3}V$$
$$	herefore$$ Charge on capacitor, $${q_1} = C\Delta V = 1 	imes {4 \over 3}\mu C$$
$${q_1} = 1.33\mu C$$

Electrostatics & Capacitance

In the circuit shown below, the switch S is connected to position P for a long time so that the charge on the capacitor becomes q 1 $\muC. Then S is switched to position Q. After a long time, the charge on the capacitor is q 2 \mu$C. The magnitude of q 1 is ________________.

Integer / Numeric Answer Type