i) ii) What is the irradiance (in W/m) that falls onto a surface that is positioned perpendicularly to the LED, as shown in the figure below, for a) r = 0 and b) an arbitrary value of r? [6 points] Assume that this surface is a Lambertian diffused reflector with a reflectance of 50% for all parts of the LED spectrum. A camera is focused onto the wall at the spot where r = 0. The lens of camera is 1 m from the wall and the camera has an entrance pupil diameter of 10 mm. The CCD array of the camera has an area of 20 x 20 mm and the optical axis of the camera subtends an angle of 30 relative to the LED forward axis. What is the total power captured by the CCD array? Please justify any approximations or assumptions that you make. CCD [14 points] LED camera lens 1 m wall 30 r=0