Light Intensity Homework: Solve for Unknown Intensity

AI Thread Summary
The problem involves a 60-cd lamp and another lamp of unknown intensity, positioned 3 meters apart, with a light meter placed 1.5 meters from the 60-cd lamp. The light meter reads equal illuminance from both lamps, leading to the equation E = P1/d1^2 = P2/d2^2. The distance from the unknown lamp to the light meter is 1.5 meters, as the total distance between the lamps is 3 meters. The key point of confusion is whether the light meter is positioned between the lamps or outside of them, which affects the calculations. Solving for the unknown intensity requires careful consideration of these distances.
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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