Which specially fabricated pn junction diode is used for detecting light intensity?

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a specially fabricated p-n junction diode used for detecting light intensity.

2. **Identifying the Diode**: The diode that is specifically designed for this purpose is called a **photodiode**.

3. **Functionality of the Photodiode**: A photodiode is a silicon diode that is specially fabricated with a transparent window. This design allows light to reach the junction of the diode, enabling it to detect light intensity.

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