Question

The device that can detect optical signals is

• A. Zener diode
• B. Photo diode
• C. Light emitting diode
• D. Transistor

Hint:

Photo diodes are specifically used for detecting light signals, making them ideal for optical signal detection.

Answer 1

The Correct Option is B

A photodiode is specifically designed to detect light (optical signals). When photons hit the photodiode, they generate electron-hole pairs, creating a photocurrent proportional to the intensity of the light. Zener diodes are used for voltage regulation, and light-emitting diodes (LEDs) emit light when current flows through them. Transistors are used for amplification and switching, not for detecting light. Thus, the correct answer is \( \boxed{\text{Photo diode}} \).