The example for non-ohmic resistance is

$A$ circuit and the signal applied at its input terminal $(V_i)$ are shown in the figure below. Which one of the options correctly describes the output waveform $(V_0)$? (Assume all the devices used are ideal and take $P$ as the reference potential.)

The current $I$ in the circuit shown below is: (All diodes are ideal and identical)

Two $PN$-junctions can be connected in series by three different methods as shown in the figure. If the potential difference across the junctions is the same,then the correct connections will be:

Write a short note on a semiconductor diode.

In the circuit shown,if the forward voltage drop for the diode is $0.5\, V$,the current in the circuit will be.....$mA$.