Question

select one:
o a. emits light when reverse biased
o b. senses light when reverse biased
o c. acts as a variable resistance when exposed to light
o d. emits light when forward biased

Explanation:

To solve this, we analyze each option:

• Option a: LEDs emit light when forward - biased, not reverse - biased. So this is incorrect.
• Option b: Photodiodes sense light when reverse - biased, but the question is about a device (likely LED or LDR? But the correct device for emitting light is LED which emits in forward bias). So this is not for the device that emits light.
• Option c: Light - dependent resistors (LDRs) act as variable resistors when exposed to light, but this is not about a device that emits light.
• Option d: Light - Emitting Diodes (LEDs) emit light when they are forward - biased. This is the correct characteristic of an LED.

Answer:

d. emits light when forward biased