Assertion : Photodiode current work in reverse bias.
Reason : Change in diode increases with increase in intensity .

Answer

To solve the assertion and reason question regarding photodiodes, we will analyze each statement step by step.

### Step 1: Analyze the Assertion
**Assertion:** Photodiode current works in reverse bias.

- **Explanation:** A photodiode is a semiconductor device that converts light into an electrical current. It operates in reverse bias mode, meaning that the voltage is applied in such a way that it widens the depletion region and allows for the generation of a photocurrent when light falls on it. In reverse bias, the photodiode can efficiently collect the charge carriers (electrons and holes) generated by the incident light, leading to a measurable current.

### Step 2: Analyze the Reason
**Reason:** Change in diode current increases with increase in intensity.

- **Explanation:** The current generated by a photodiode is directly proportional to the intensity of the light incident on it. As the intensity of light increases, more photons hit the photodiode, leading to the generation of more electron-hole pairs. This results in an increase in the photocurrent. Therefore, the statement is correct.

### Step 3: Determine the Relationship Between Assertion and Reason
- Both the assertion and the reason are true statements. However, the reason provided does not correctly explain why the photodiode operates in reverse bias. The assertion focuses on the operational mode of the photodiode, while the reason discusses the relationship between light intensity and current generation.

### Conclusion
- **Final Answer:** The assertion is true, and the reason is true, but the reason is not a correct explanation of the assertion.