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Optoelectronics, Optics, Lights and Lasers > Non-Coherent Light Sources > Combustion > 

How do I set this up using the formula below?

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Author Topic: How do I set this up using the formula below?  (Read 2176 times)
RolloutGuy
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« on: May 15, 2011, 03:36:29 PM »
The intensity 'E' (in foot-candles) of light falling on a surface is related to the distance 'd' (in feet) between the light source and the surface by:

d^2 = 1 / 'E'

The electricity goes out and you are reading a book by candlelight. The intensity of the light on the page is 8 foot-candles.

How far is the flame from the book?
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Keith
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« Reply #1 on: May 15, 2011, 03:40:26 PM »
d^2 = 1 / E

. . . E = 8

d^2 = 1 / 8

d = sqrt(1 / Cool ... about 0.35355 feet ... or about 4 1/4 inches
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