Match List - I with List - II.
| List – I | List – II | ||
|---|---|---|---|
| (A) | Zener diode | (I) | operates under forward bias |
| (B) | LED | (II) | operates under reverse bias |
| (C) | Solar cell | (III) | operates under reverse bias in break down region |
| (D) | Photo diode | (IV) | no biasing is applied |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
Each device is used in the bias condition that suits its working.
(A) Zener diode — this matches (III) operates under reverse bias in break down region. A Zener diode is a heavily doped diode used as a voltage regulator in its reverse breakdown region.
(B) LED — this matches (I) operates under forward bias. Light is emitted when electrons and holes recombine in a forward-biased junction.
(C) Solar cell — this matches (IV) no biasing is applied. It generates a voltage from absorbed light by itself and delivers current to the load without an external bias.
(D) Photo diode — this matches (II) operates under reverse bias. In reverse bias the light-generated carriers change the small reverse current measurably.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic was removed from the latest NCERT book (2026-27), and it also appears to be out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Zener Diode – “… It is designed to operate under reverse bias in the breakdown region and used as a voltage regulator.”
Light Emitting Diode – “… It is a heavily doped p-n junction which under forward bias emits spontaneous radiation.”
Solar Cell – “… It works on the same principle (photovoltaic effect) as the photodiode, except that no external bias is applied and the junction area is kept much larger for solar radiation to be incident because we are interested in more power.”
Photodiode – “… Hence, photodiodes are preferably used in the reverse bias condition for measuring light intensity.”