How Do You Solve These Basic Illumination Problems?

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SUMMARY

The discussion focuses on solving basic illumination problems using the formula for intensity, I = L / R², where I represents intensity, L is luminous flux, and R is the distance from the light source. The first problem calculates the illumination at a distance of 4.2 meters from a 415 lumen lamp, yielding an intensity of approximately 23.5 lux. The second problem involves finding the distance of a second lamp from a screen, given its luminous flux of 2350 lumens, while the first lamp is 2.7 meters away with a flux of 1445 lumens. The final problem determines the intensity of a second lamp positioned 5 meters from the screen, given the first lamp's intensity of 101 candela at 4 meters.

PREREQUISITES
  • Understanding of luminous flux and its measurement in lumens.
  • Knowledge of light intensity and its measurement in candelas.
  • Familiarity with the inverse square law in illumination.
  • Basic algebra for solving equations involving distance and intensity.
NEXT STEPS
  • Study the application of the inverse square law in different lighting scenarios.
  • Learn how to calculate illumination levels using various luminous flux values.
  • Explore the relationship between distance and light intensity in practical lighting design.
  • Investigate the effects of different lamp types on illumination and intensity.
USEFUL FOR

Students in physics or engineering, lighting designers, and anyone interested in understanding the principles of illumination and light intensity calculations.

drunkenfool
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1) Find the illumination 4.2 m below a 415 lm lamp.

2) A screen is placed between two lamps so that they illuminate the screen equally. The first lamp emits a luminous flux of 1445 lm and is 2.7 m from the screen. What is the distance of the second lamp from the screen if the luminous flux is 2350 lm?

3) Two lamps illuminate a screen equally. The first lamp has an intensity of 101 cd and is 4 m from the screen. The second lamp is 5 m from the screen. What is the intensity of the second lamp?

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These should be very easy. However, I'm doing this for a friend and I don't have his book or any of the formulas. Help me out?
 
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Intensity is proportional to the inverse square of radius.

I = L / R^2, this should help you solve all three of hte above questions, since they are basically the same.
 
I = L / R^2
i = 415/4.2^2
 

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