In the given circuit,the voltage across the $P-N$ junction diode remains constant at $0.5 \ V$ regardless of the current. The maximum power rating of the diode is $100 \ mW$. What should be the value of $R$ in $\Omega$ to obtain the maximum current in the circuit?

Two ammeters $A_1$ and $A_2$ are connected as shown in the given figure. By neglecting the internal resistance of the ammeters, the reading in the meter $A_1$ is (in $\text{A}$)

Statement $I :$ When a $Si$ sample is doped with Boron,it becomes $P$-type and when doped by Arsenic it becomes $N$-type semiconductor such that $P$-type has excess holes and $N$-type has excess electrons.
Statement $II$ : When such $P$-type and $N$-type semiconductors are fused to make a junction,a current will automatically flow which can be detected with an externally connected ammeter.
In the light of above statements,choose the most appropriate answer from the options given below.

The change in current through a junction diode is $12 \, mA$ when the forward bias voltage is changed by $0.6 \, V$. The dynamic resistance is

If in a $p-n$ junction diode,a square input signal of $10\, V$ (varying from $+5\, V$ to $-5\, V$) is applied as shown,then the output signal across $R_L$ will be:

The $V-I$ characteristic of a silicon diode is shown in the Figure. Calculate the resistance of the diode at $(a) \; I_{D} = 15 \, mA$ and $(b) \; V_{D} = -10 \, V$.