<p>The VI characteristics of a PN junction diode are shown for forward and reverse bias.</p>

<p><img alt="" src="https://school.achievam.com/upload/questionbank/question/que_1758586515.jpg" style="height:200px; width:302px" /></p>

<p>(i) Explain why the diode offers variable resistance in forward bias. Does it obey Ohm&rsquo;s law?<br />
(ii) Why does the diode current increase sharply only after a certain voltage in forward bias?<br />
(iii) Why is the reverse current very small during reverse bias, and what causes it?</p>