In a photo-diode:
A) The photocurrent is proportional to incident light intensity
B) Photocurrent is inversely proportional to incident light intensity
C) Photocurrent is independent of the incident light intensity
D) Incident light intensity is proportional to the photocurrent.

Hint: Photocurrent: It is defined as the electric current through the photodiode as a result of exposure of power.
Photodiode: Photodiode is also called a photosensor or light detector or photodetector. It is defined as a type of PN junction device that produces current when exposed to light. It operates in reverse biased mode.
Photodiode works on the principle of the Photoelectric effect. When a photon of sufficient energy strikes the diode, it creates an electron-hole pair. This mechanism is called an inner photoelectric effect. The working principle of the photodiode is the conversion of light into current.

Complete solution:
Photodiode is a lightweight sensor. A photodiode is a device that converts light energy to electrical energy.
With the increases in the number of electron-hole pairs produced at the junction, there will be an increase in the intensity of light. Photodiode operates on two modes. They are Photovoltaic mode and Photoconductive mode.
There are many types of photodiodes are PN photodiode, a PIN photodiode, avalanche photodiode, Schottky photodiode. The semiconductors which are used for making different types of photodiode are Silicon, Germanium, Indium Gallium Arsenide, etc., Some Photodiodes are like light-emitting diode.
In a photodiode, photocurrent is directly proportional to the intensity of incident light. The more the incident light intensity, the more will be the current.

Answer is option (A), Photocurrent is proportional to incident light.

Note: Photodiodes are used in an optical communication system and burglar alarm systems. It is mainly used in counters and switching circuits
Advantages: It is a low-cost device, It provides a linear response, It gives high operational speed and Lightweight and compact.
Disadvantages: Photodiodes are temperature-dependent devices.