Problem Set 6: Radiometry

Problem Set 6: Radiometry#

Calculate the optical power emitted by a 5 mm red LED with the following specifications. Assume that the LED is a monochromatic source.
- Luminous intensity: 8000 mcd
- Viewing angle: 30 degrees
- Center wavelength: 630 nm
Your night light has a luminous flux of 10 lm. What is the illuminance on your optics book located 2 m away from the light in units of lux? Assume that the light has isotropic emission and use a point source approximation.
A laser tag system is constructed using a red LED, a silicon photodiode, and an amplifier. The LED and photodiode specifications are at the end of the assignment. The amplifier has a gain of 106 V/A. What is the voltage signal received if the LED and photodetector are separated by 30 m?
Table 5.3 in the book states that the illuminance with a full moon is 0.1 lux. Using this information calculate the luminance of the moon in units of cd/m2.
A picture is taken of asphalt outside during the day. The height of the camera is 1 meter and the asphalt is 10 m away. If the camera has an effective focal length of f=50mm, F/2.8, pixel size of \(2 \mu m\), and total transmission of 80%. What is the light flux that hits the central CCD pixel? The answer should be in lumens. Use an illuminance (see Table 5.3) of E=104 lux. Assume that asphalt is a perfect Lambertion reflector with a reflectivity of 10% (see http://geography.about.com/od/physicalgeography/a/solarradiation.htm).
Problem 5.15. (Assume that there is a diffuser sheet immediately before the slide. The diffuser sheet takes all of the incident flux and scatters it to become Lambertian over an entire hemisphere. Use a tungsten-halogen lamp and calculate the collection angle between the lamp and the diffuser sheet.)