Final answer:
The correct answer is that as you increase the distance, the intensity of photons in the beam decreases, due to the inverse square law where light intensity diminishes with the square of the distance.
Step-by-step explanation:
If you increase distance, the intensity of photons in the beam decreases. This is because of the inverse square law which states that the intensity of light (or any electromagnetic radiation) from a point source is inversely proportional to the square of the distance from the source. To understand this, imagine a beam of light spreading out as it moves away from its source. As the light spreads over a larger area, the same number of photons is distributed over a greater space, making the light intensity lessen. For instance, if the distance from the light source is doubled, the area over which the light is spread is quadrupled, leading to a reduction in intensity by a factor of four.