Calculating distance between lux meter and light source

In summary, the conversation discusses the use of the inverse square law to calculate the distance between a light source and a lux meter. It is noted that this law may not work for sources with significant area or for laser sources due to their distributed nature. It is suggested to conduct an experiment to determine the distance at which the inverse square law becomes effective.
  • #1
san-yas
1
0
I am currently performing some experiments to calculate the distance between a light source and a lux meter where the light source points directly towards the lux meter.
Is it possible to calculate the exact distance between the light source and the lux meter given that we have a lux value (through the lux meter) and the luminosity flux (through the information given by the light source manufacturer)? or is the inverse square law (lux=lm/d^2) subjected to particular conditions?
 
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  • #2
Welcome to PF.

It seems like the inverse square law should work for this. What have you seen in your experimental data so far?
 
  • #3
san-yas said:
a light source
If the source has a significant area then ISL will stop working close up. Also, if the source is a laser, you will have a problem because the effective position of the source can be may metres behind the front (multiple mirror images, as with an infinity mirror) and the r in 1/r2 would need to be corrected for. ISL is fine for stars and planets but the Moon and Sun are very much distributed sources.

I would be inclined to do the experiment first and find what distance the ISL begins to work for.
 
  • Informative
Likes berkeman

1. How do I calculate the distance between a lux meter and a light source?

To calculate the distance between a lux meter and a light source, you will need to measure the illuminance (lux) at a known distance from the light source and then use the inverse square law to calculate the distance. The inverse square law states that the intensity of light is inversely proportional to the square of the distance from the source. So, if you double the distance, the illuminance will decrease by a factor of four.

2. What is the inverse square law?

The inverse square law is a principle in physics that describes the relationship between the intensity of light and the distance from the light source. It states that the intensity of light is inversely proportional to the square of the distance from the source. This means that as the distance from the source increases, the intensity of light decreases exponentially.

3. Can I use a lux meter to measure the distance to a light source?

No, a lux meter is used to measure the illuminance (lux) at a specific point, not the distance to a light source. To calculate the distance, you will need to use the inverse square law and measure the illuminance at a known distance from the source.

4. What factors can affect the accuracy of distance calculations using a lux meter?

There are several factors that can affect the accuracy of distance calculations using a lux meter. These include the type and intensity of the light source, the sensitivity of the lux meter, and any obstructions or reflections that may affect the measurement.

5. How can I ensure accurate distance calculations using a lux meter?

To ensure accurate distance calculations using a lux meter, it is important to use a high-quality lux meter with a wide measuring range and a high level of sensitivity. It is also important to take multiple measurements at different distances and to account for any obstructions or reflections that may affect the measurement.

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