hw7_Lighting Calculation

# hw7_Lighting Calculation - θ of the incident light E = I/d...

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School of Architecture University of Florida ARC 4620 Environmental Technology 2 Gary W. Siebein Fall 2004 Dan Butko, Youngmin Kwon, Koyel Sikdar, Pattra Smitthakorn LIGHT DISTRIBUTION: Inverse Square Law and Cosine Law Show all your calculations Name: d 1. Light distribution by distance and inverse square law: The illuminance from a point source is inversely proportional to (distance) 2 . E= I/d 2 where E= Illumination level in foot candles I= Light intensity in candelas d= distance in feet from the light source Question: An incandescent lamp has a light intensity of 400cd. Based on the principle of Inverse square law, what is the Illumination Level at 2 ft from the light source? And at 4 ft? 2. Light distribution at a fixed distance and cosine law: The illuminance changes with cosine of the angle (

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Unformatted text preview: θ ) of the incident light E = I/d 1 2 E θ = (I/d 2 2 ) × cos θ Question: A ceiling light fixture has a candlepower of 1000cd and is considered as a point source. A work plane (Desk A) is positioned right below the light fixture. Assume that reflection from major surfaces such as ceiling and walls is not significant and that there are no other light sources in the room.The distance between the light fixture and the top surface of Desk A is 5ft, and the incident angle of the incoming light ( θ ) onto Desk B is 60 o .Calculate the Illumination Level E 1 and E 2 respectively. d 1 d 2 School of Architecture University of Florida ARC 4620 Environmental Technology 2 Gary W. Siebein Fall 2004 Dan Butko, Youngmin Kwon, Koyel Sikdar, Pattra Smitthakorn...
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## This note was uploaded on 08/27/2011 for the course ARC 4620 taught by Professor Staff during the Fall '08 term at University of Florida.

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hw7_Lighting Calculation - θ of the incident light E = I/d...

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