The intensity, Io, of a light source is reduced to I after passing through d meters of fog according to the formula I = Ioe−0.12d. If 1,200 lumens of light are present initially, what is an equivalent expression written as a percentage rate of lumens lost?

Guest Feb 14, 2017

#1**0 **

ORIGINAL lumens = 1200 l

NEW intensity = 1200 e^(-.12d) lumens

Difference (the amount of change) = 1200 - 1200 e^(-.12d) over a distance 'd '

Percentage change

(1200-1200 e^(-.12d) )/1200 x 100

Percentage RATE of change (average over distance d) would be this divided by d

percentage rate of change (1200-1200e^(-.12d)) / (1200 d) x 100 = (1 - e^(-.12d))/d x 100

ElectricPavlov
Feb 14, 2017