How can I correlate the light intensity and energy?

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Discussion Overview

The discussion revolves around correlating light intensity and energy to predict the evaporation of water in a solar oven. Participants explore measurement methods, units of light intensity, and the relationship between illuminance and energy output.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant seeks to determine the energy associated with a specific light intensity to predict water evaporation in a solar oven.
  • Another participant questions the unit of measurement for light intensity, suggesting that using candela may complicate the energy calculation due to wavelength dependence.
  • A participant mentions using an Arduino system to measure electric current from sunlight and expresses difficulty in programming it to convert readings to candela.
  • Concerns are raised about the necessity of converting illuminance to luminous intensity in candela when the goal is to find energy output.
  • Participants discuss the change in measurement approach to using lux for illuminance and express a desire to convert this to energy in watts per square meter.
  • There is a suggestion to use known values for solar intensity instead of measuring it, highlighting the vagueness of the initial posts and the need for clearer information.

Areas of Agreement / Disagreement

Participants express differing views on the best approach to measure light intensity and its conversion to energy, indicating that multiple competing methods and understandings exist. The discussion remains unresolved regarding the optimal measurement technique and the relationship between light intensity and energy.

Contextual Notes

Limitations include the dependence on specific measurement methods and units, as well as the potential for missing assumptions about the solar oven's efficiency and the characteristics of the light source.

_Gandalf_
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I need to know how much energy will I have for a certain intensity of ligh, I need this because I want to predict how much water will my solar oven evaporate for this light intesity (I can mesure the light intensity). I'd be very thankful if anyone helped me on this because I've searched a lot I have made no progress
 
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In what unit are you going to measure the light intensity?
 
In candles
 
Then you will have a hard time to find the energy. The luminous intensity measured din candela depends on the wavelength of the light.
If you have a continuous spectral distribution, the intensity in candela will be given by a integral over all the wavelengths.
How are you actually measuring it? You have an instrument that gives you intensity in candela?
 
Yes, I'm using and Arduin system that mesures the eletric current that the sun produces, then I use a table to convert it (actually I'm trying to make it give automatically the result in candela, buut I'm not very good at programming)
 
How does the sun produce that electric current? You are using some sensor, aren't you?
Anyway, if you want to know the energy, why bother to convert to luminous intensity in candela?
I thought you already have an instrument that gives readings in candela and you want to find the energy. But your last post does not fit this scenario.

You may get better answers if you say from the beginning the complete story rather than leaving out pieces that may be essential (even if you thin they aren't).
 
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Ok I'll try. I can mesure the iluminance of the light, in lux, (yes, I changed the way I mesure), so I use a resistor that gives a value that I useto get value of the iluminance. Now I have the luminance and I want to convert it into energy, or something that gives me the result in W/m^2, because O want to predict how much water will my solar oven evaporate given a certain quantity of iluminance. My solar oven is composed of a aerial with more than 300 pieces of glass glued on it, I can consider it a perfect reflector.
 
How is the resistor giving a value? What kind of value? And what kind of resistor?
 
_Gandalf_ said:
Ok I'll try. I can mesure the iluminance of the light, in lux, (yes, I changed the way I mesure)...
Great! Can you change the way you measure to give you watts per square meter?
...want to predict how much water will my solar oven evaporate given a certain quantity of iluminance. My solar oven is composed of a aerial with more than 300 pieces of glass glued on it, I can consider it a perfect reflector.
Can't you just use the known value for the sun's intensity? Why do you even need to measure it?

I agree with @nasu that your posts are so vague that it is difficult to help you.
 

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