The time in seconds required to produce a potential difference of $20 \ V$ across a capacitor of $1000 \ \mu F$ when it is charged at a steady rate of $200 \ \mu C/s$ is

In the circuit given,the charge on the capacitor is

When the key $K$ is pressed at time $t = 0$, which of the following statements about the current $I$ in the resistor $AB$ of the given circuit is true?

Two identical capacitors $A$ and $B$,charged to the same potential $V$,are connected in two different circuits as shown below at time $t=0$. If the charge on capacitors $A$ and $B$ at time $t=CR$ is $Q_{A}$ and $Q_{B}$ respectively,then (Here $e$ is the base of natural logarithm):

When a lamp is connected in series with a capacitor,then:

In the circuit shown below,the key is pressed at time $t=0$. Which of the following statement$(s)$ is(are) true?
$(A)$ The voltmeter displays $-5 \ V$ as soon as the key is pressed,and displays $+5 \ V$ after a long time.
$(B)$ The voltmeter will display $0 \ V$ at time $t=\ln 2 \ s$.
$(C)$ The current in the ammeter becomes $1/e$ of the initial value after $1 \ s$.
$(D)$ The current in the ammeter becomes zero after a long time.