The $n$-side of the depletion layer of a $p-n$ junction

If a $p-n$ junction diode is forward biased, then:

Consider a $p-n$ junction as a capacitor, formed with $p$ and $n$-materials acting as thin metal electrodes and depletion layer width acting as separation between them. Basing on this, assume that an $n-p-n$ transistor is working as an amplifier in $CE$ configuration. If $C_1$ and $C_2$ are the base-emitter and collector-emitter junction capacitances, then :

In the following circuit,the reading in the ammeter is (in $mA$)

What is the current flowing through the given circuit? $A$ given diode is an ideal diode.

Consider a circuit consisting of a capacitor $(20 \mu\text{F})$, a resistor $(100 \Omega)$, and two identical diodes connected in anti-parallel as shown in the figure. The resistance of each diode under forward biasing condition is $10 \Omega$. The time constant of the circuit is $\alpha \times 10^{-3} \text{ s}$. The value of $\alpha$ is . . . . . . .