What is the difference between Luminous intensity and intensity of illumination? What is the difference between the Luminous intensity and intensity of illumination? Please explain with units and dimensions as well! I googled but I partially understood it!
 A: From this Wikipedia article:
The luminous intensity for monochromatic light of a particular wavelength λ is given by:
$$I_{\nu}=683\cdot \bar y(\lambda)\cdot I_e,$$
where
$I_{\nu}$ is the luminous intensity in candelas (cd),
$I_e$ is the radiant intensity in watts per steradian  (W/sr),
$\bar y(\lambda)$ is the standard luminosity function.
If more than one wavelength is present (as is usually the case), one must sum or integrate over the spectrum of wavelengths present to get the luminous intensity:
$$I_{\nu}=683\int_0^\infty\bar y (\lambda)\frac{dI_e(\lambda)}{d\lambda}d\lambda$$
Here one can read:

Intensity of illumination. Optics: the intensity of light falling at a given place on a lighted surface; the luminous flux incident per unit area, expressed in lumens per unit of area.

The luminous intensity corresponds with radiation coming from an object while the intensity of illumination corresponds with the radiation falling upon an object.
What more can I write? You can compare the two easily and discover the difference.
