The resistance of a germanium junction diode whose $V-I$ characteristic is shown in the figure is ........ $k\Omega$ $(V_k = 0.3 \, V)$.

$Ge$ and $Si$ diodes start conducting at $0.3\,V$ and $0.7\,V$ respectively. In the following figure,if the $Ge$ diode connection is reversed,the value of $V_0$ changes by: ...... $V$ (assume that the $Ge$ diode has a large breakdown voltage).

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

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

Two identical $P-N$ junctions are connected in series with a battery in three ways as shown in the figure. In which two circuits will the potential difference across the $P-N$ junctions be equal?

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: $A$ diode under reverse-biased condition provides very small current which is nearly independent of voltage until a critical limit at which the current increases drastically.
Reason $R$: Below the critical voltage limit, only majority charge carriers flow which increases drastically above critical voltage.