The barrier potential of a $P-N$ junction diode does not depend on:

When and why is a $p-n$ junction called forward biased? Describe the changes that occur under such bias.

Can the potential barrier across a $p-n$ junction be measured by simply connecting a voltmeter across the junction?

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

The $V-I$ characteristic of a diode is shown in the figure. The ratio of forward to reverse bias resistance is

Among the diodes shown in the following diagrams,which one is reverse biased?