Define the term "Intensity" in photon picture of electromagnetic radiation.

Explanation

### Step-by-Step Solution:

1. **Definition of Intensity**:
- Intensity (I) in the context of electromagnetic radiation refers to the total amount of energy that falls on a given surface area per unit time. It quantifies how much energy is being delivered to a specific area over a certain period.

2. **Mathematical Representation**:
- The intensity can be mathematically expressed as:
\[
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