Converting source intensity to the maximum reach of beam flux

In summary, the equation E = 10.76*(35,000/d^2) can be used to solve for the maximum 5 lux illumination distance, but the given distance of 275 feet is not accurate. The equation does not include mounting height and a right triangle setup is not necessary.
  • #1
Qube
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Homework Statement
Consider a headlamp that is measured to have an intensity of 35,000 candela at FMVSS 108 test point 1.5D, 2R. That is, 1.5 degrees below the horizontal axis and 2 degrees right of the vertical axis with respect to the lamp. On a completely unlit road, what is the maximum distance at which there is 5 lux illumination?
Relevant Equations
E = 10.76*(I/d^2)
We can solve for the maximum 5 lux illumination distance with the above equation.

E = 10.76*(35,000/d^2)

d = 275 feet (approximately).

However, the 5 lux illumination distance is not 275 feet. The 35,000 cd value is not an axial intensity value. It is at a point that is slightly down and to the right with regard to the intersection of the lamp's horizontal and vertical axes (H-V).

Therefore, we have to set up a right triangle as such:

IMG_20190727_171557.jpg


Is this the correct setup? Note that we cannot solve this problem as stated, since no mounting height of the lamp is given.
 
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  • #2
No, this is not the correct setup. The equation given is E=10.76*(35000/d^2), where E is the lux illumination and d is the distance from the lamp. There is no mention of mounting height in the equation.
 

1. How do you calculate the maximum reach of beam flux?

The maximum reach of beam flux is calculated by taking the source intensity and dividing it by the beam flux. This will give you the distance that the beam can reach at its maximum intensity.

2. Can you explain the concept of source intensity and beam flux?

Source intensity refers to the amount of energy or radiation emitted from a source. Beam flux, on the other hand, refers to the rate at which the energy or radiation is delivered per unit area. In simpler terms, it is the concentration of the source intensity at a given distance.

3. What are the units of measurement for source intensity and beam flux?

Source intensity is typically measured in watts per square meter (W/m^2) while beam flux is measured in watts per square centimeter (W/cm^2).

4. How does the conversion from source intensity to beam flux affect the maximum reach of the beam?

The conversion from source intensity to beam flux does not directly affect the maximum reach of the beam. However, it helps to determine the intensity of the beam at a certain distance and thus, indirectly affects the maximum reach.

5. Are there any other factors that can affect the maximum reach of beam flux?

Yes, there are other factors that can affect the maximum reach of beam flux such as the type and power of the source, atmospheric conditions, and any obstructions in the path of the beam.

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