$A$ crystal diode is a:

For an ideal diode,the current in the following arrangement is:

Find the current $i$ in the circuit shown.

Can we take one slab of $p-$type semiconductor and physically join it to another $n-$type semiconductor to get $p-n$ junction?

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 :

The current in the following circuit is: