Light Intensity Homework: Solve for Unknown Intensity

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SUMMARY

The discussion centers on calculating the intensity of an unknown lamp using the formula for illuminance, E = P/d². Given a 60-candela (cd) lamp and the distance of 3 meters between the lamps, the light meter is positioned 1.5 meters from the 60-cd lamp. By applying the equation E = P1/d1² = P2/d2², participants aim to determine the intensity of the second lamp based on the equal illuminance readings from both sources.

PREREQUISITES
  • Understanding of illuminance and its measurement in candelas (cd).
  • Familiarity with the formula E = P/d² for calculating light intensity.
  • Knowledge of distance measurement in physics, specifically in relation to light sources.
  • Basic algebra skills for solving equations involving variables.
NEXT STEPS
  • Review the principles of light intensity and illuminance in physics.
  • Practice solving problems using the formula E = P/d² with various scenarios.
  • Explore the concept of inverse square law in relation to light sources.
  • Investigate the effects of distance on light intensity and practical applications in lighting design.
USEFUL FOR

Students studying physics, educators teaching light intensity concepts, and anyone involved in practical applications of lighting and illuminance measurements.

J89
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Homework Statement


A 60-cd lamp and a lamp of unknown intensity are placed 3m apart. A light meter is moved between the two lamps until it reads the same illuminance from both lamps. The light meter is then 1.5 m away from the 60-cd lamp. What is the intensity of the other lamp?


Homework Equations


E=P/d^2



The Attempt at a Solution


No clue
 
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J89 said:

Homework Statement


A 60-cd lamp and a lamp of unknown intensity are placed 3m apart. A light meter is moved between the two lamps until it reads the same illuminance from both lamps. The light meter is then 1.5 m away from the 60-cd lamp. What is the intensity of the other lamp?

Homework Equations


E=P/d^2

Use E = P1/d1^2 = P2/d2^2.
The point is whether the light meter is between the two lamps or outside the two lamps?
 

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