Factors that affect the intensity of light from a source

Intensity is the power transferred per unit area. When light comes out from a source, it diffracts or spreads out with distance, decreasing the intensity. Intensity is inversely proportional to the square of distance from the light source. So the distance of the source affects light intensity.

Another factor that affects the intensity of light is the power of the source. E. g a bulb with a higher power will produce light that has higher intensity.

As E = hf, using higher frequency light will increase the intensity, by increasing the energy of the incident light.