Problem Set 3

Question 1

Find the average illuminance for the following categories. Cite your sources, provide units, and remember about significant figures.

  • Sunlight Indoor household lighting
  • Recommended lighting for reading
  • Moonlight
  • Workshops

Question 2

  1. Estimate/calculate the total energy consumed by the lighting you identified this past week, as well as the average power associated with that lighting. Show your work.
  2. When was lighting excessive? Insufficient?
  3. What lighting technology or technologies most interested you from Wednesday's lecture? Why?

Question 3

Estimation. Normal commercial LEDs are rated at 40 lumens/watt. Suppose you want to design a reading light for households that is placed 50 cm from the reading material. How many LEDs would you use in your light that are rated at 20 mA and 3.6 V? Show all your calculations.

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