The $P-N$ junction depletion layer is made up of .......

Refer to the circuit diagram given in the figure. Which of the following observations are correct?
$A.$ Total resistance of the circuit is $6 \ \Omega$.
$B.$ Current in the ammeter is $1 \ A$.
$C.$ Potential across $AB$ is $4 \ V$.
$D.$ Potential across $CD$ is $4 \ V$.
$E.$ Total resistance of the circuit is $8 \ \Omega$.
Choose the correct answer from the options given below:

When a reverse bias is applied to a p-n junction, it . . . . . . .

Current $I$ through a given $p-n$ junction when a voltage $V$ is applied across it is given by $I = I_0 \left( e^{\frac{V}{2 V_T}} - 1 \right)$, where $I_0$ and $V_T$ are constants. If $r_d(I)$ is the dynamic resistance of the junction, then $r_d(1000 I_0) = \alpha r_d(10 I_0)$, where $\alpha$ is approximately equal to

If a diode having infinite reverse bias resistance is connected in a circuit as shown in the figure,then $I_1$ and $I_2$ are respectively:

The barrier potential of a $p-n$ junction depends on:
$(1)$ Type of semiconductor material
$(2)$ Amount of doping
$(3)$ Temperature
Which one of the following is correct?