Discharging of Capacitors

Q. A $1\mu F$ capacitor holding a charge of $1\times {10}^{-5}C$ is connected to a $10\Omega$ resistor via switch.

What current will flow after the switch is closed?

1. $0$
2. ${10}^{-5}A$
3. $1A$
4. $10A$

Q. A capacitor of $2\mu F$ is charged as shown in the diagram. When the switch $S$ is turned to position 2, the percentage of its stored energy dissipated is :

1. $0\%$
2. $20\%$
3. $75\%$
4. $80\%$

Q. If a capacitor of $10\mu F$ is charged to 10V and then connected to a new circuit to discharge through a $10\Omega$ resistor, what is the charge on it after $20\mu s$?

1. $72\mu C$
2. $92\mu C$
3. $82\mu C$
4. $62\mu C$

Q. Two capacitors $\text{A}$ and $\text{B}$ with capacitances $15\mu \text{F}$ and $5\mu \text{F}$ are charged to potential difference of $5\text{V}$ and $9\text{V}$ respectively. Consider a wire connected to each cepacitor as shown (with free ends). An uncharged capacitor $5\mu \text{F}$ with lead wire falls on the free ends to complete the circuit. Find how much amount of heat produced in the circuit?

1. $210\mu \text{J}$
2. $180\mu \text{J}$
3. $67.5\mu \text{J}$
4. $390\mu \text{J}$

Q. A capacitor having charge Q connected to R, at t=0. After 1 time constant, the charge left on the capacitor is,

1. 0.63 Q
2. 0.37 Q
3. 0.5 Q
4. \N