Calculating Intensity & Distance Ratios of Two Identical/Similar Lights

In summary, the first problem involves two identical stars with an intensity ratio of 40 to 1. The question is asking for the ratio of their distances. The second problem involves two similar lights with a distance ratio of 8 to 785. The task is to calculate the ratio of intensities. The formulas used for both problems are E1D1^2 = E2D2^2, where E is illumination, D is distance, and I is intensity.
  • #1
dranseth
87
0

Homework Statement



Two identical stars have intensity readings in a 40 to 1 ratio. Calculate the ratio of their distances.

Two similar lights are at distances in a ratio of 8 to 785. Calculate the ratio of intensities.


All I want to know is if I use E1D1^2=E2D2^2 or I1/D1^2=I2/D2^2. I'm quite sure I use E1D1^2=E2D2^2 for both. For the first one because they stars are the exact same, and for the second one because they are similar?
 
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  • #2
you'll have to tell us what E, D, and I are.
 
  • #3
E= illumination
D=distance
I=intensity
 

1. What is the formula for calculating intensity ratio between two lights?

The formula for calculating intensity ratio between two lights is: Intensity Ratio = (I1)^2 / (I2)^2, where I1 and I2 are the intensities of the two lights.

2. How do you determine the distance ratio between two lights?

To determine the distance ratio between two lights, you can use the inverse square law which states that the intensity of light is inversely proportional to the square of the distance from the source. The formula for distance ratio is: Distance Ratio = (D1)^2 / (D2)^2, where D1 and D2 are the distances from the first and second light source, respectively.

3. Can the intensity and distance ratios be calculated for non-identical or non-similar lights?

No, the intensity and distance ratios can only be calculated for identical or similar lights. This is because the inverse square law only applies to lights that have the same properties, such as wavelength and intensity.

4. Why is it important to calculate intensity and distance ratios for two lights?

Calculating intensity and distance ratios allows us to compare the relative brightness of two lights and understand how their brightness changes with distance. This information is useful in various fields such as photography, astronomy, and lighting design.

5. Are there any limitations to using intensity and distance ratios for comparing lights?

Yes, there are some limitations to using intensity and distance ratios. The inverse square law assumes that the light sources are point sources, which may not be the case in real-life scenarios. Additionally, other factors such as atmospheric conditions and light absorption can also affect the intensity and distance ratios.

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