Match the LIST-I with LIST-II
| LIST-I | LIST-II | ||
| A. | p-n junction diode under forward bias | I. | High resistance |
| B. | p-n junction diode under reverse bias | II. | Low resistance |
| C. | A diode as a rectifier | III. | Sudden increase in current |
| D. | A diode at breakdown voltage | IV. | Conversion of ac to dc |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → A - II, B - I, C - IV, D - III
A p-n junction diode conducts easily only when it is forward biased; this one-way conduction decides all four matches.
(A) p-n junction diode under forward bias — this matches (II) Low resistance. Forward bias lowers the barrier, so a large current flows for a small voltage.
(B) p-n junction diode under reverse bias — this matches (I) High resistance. Reverse bias raises the barrier and only a tiny minority-carrier current (of the order of microamperes) flows.
(C) A diode as a rectifier — this matches (IV) Conversion of ac to dc. Because it conducts in one half-cycle only, the diode lets current through in one direction and so rectifies ac.
(D) A diode at breakdown voltage — this matches (III) Sudden increase in current. At the breakdown voltage the reverse current rises sharply while the voltage stays almost constant (the principle of the Zener diode).
NCERT (2026-27):
p-n Junction Diode Under Reverse Bias – “… The current under reverse bias is essentially voltage independent upto a critical reverse bias voltage, known as breakdown voltage (Vbr). When V = Vbr, the diode reverse current increases sharply.”
p-n Junction Diode Under Reverse Bias – “… The forward bias resistance is low as compared to the reverse bias resistance. This property is used for rectification of ac voltages as discussed in the next section.”