Understanding the Difference between Radiance and Irradiance

[funcosed]

Radiance, Irradiance?

Homework Statement

Hi, just wondering if my understanding of the difference between these two is correct??

Homework Equations

If radient energy is the energy transported by electromagnetic radiation then radiance is the radient energy crossing a surface per unit time that is traveling normal to the surface.
Irradience is the radient energy crossing the surface from all directions (hemisphere above the surface.

The Attempt at a Solution

 

[Delphi51]

Wow, what a collection of terminology these radiometry people have!
I think you may be mistaken about "radiance":
http://en.wikipedia.org/wiki/Irradiance