Match List - I with List - II.
| List - I | List - II |
| (Electronic device) | (Use/Application) |
| (A) Photo diode | (I) Remote controls |
| (B) Zener diode | (II) Amplifier |
| (C) Light emitting diode | (III) Voltage regulator |
| (D) Transistor | (IV) Photo detector |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A) - (IV), (B) - (III), (C) - (I), (D) - (II)
Each device is matched to the job its working principle suits.
(A) Photo diode — this matches (IV) Photo detector. In reverse bias its current changes with the intensity of light falling on the junction, so it detects optical signals.
(B) Zener diode — this matches (III) Voltage regulator. In reverse breakdown the voltage across it stays almost constant even when the current changes.
(C) Light emitting diode — this matches (I) Remote controls. A forward-biased LED emits light; infrared LEDs send the signals of remote controls.
(D) Transistor — this matches (II) Amplifier. A small change in base current controls a large change in collector current.
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):
Optoelectronic Junction Devices – “… (i) Photodiodes used for detecting optical signal (photodetectors).”
Zener Diode – “… It is designed to operate under reverse bias in the breakdown region and used as a voltage regulator.”
Optoelectronic Junction Devices – “… These LEDs find extensive use in remote controls, burglar alarm systems, optical communication, etc.”
Transistor: Structure and Action – “… Basically, it was invented to function as an amplifier, a device which produces a enlarged copy of a signal.”