Which of the diode circuits shows the correct biasing used for the measurement of the dynamic resistance of a $p$-$n$ junction diode?

When a silicon $PN$ junction is in forward biased condition with a series resistance,it has a knee voltage of $0.6\, V$. The current flowing through it is $5\, mA$ when the $PN$ junction is connected to a $2.6\, V$ battery. The value of the series resistance is.....$\Omega$.

When a $P-N$ junction is forward biased,which of the following is true?

The example for non-ohmic resistance is

For the circuit shown in the figure,the equivalent resistance between points $A$ and $B$ for two cases $(i)$ $V_A > V_B$ and (ii) $V_B > V_A$ is $\qquad \Omega$ and $\qquad \Omega$ respectively. ($D_1$ and $D_2$ are ideal diodes)

In the given figure,which of the diodes are forward biased?