Inverse Square Law concerning Light

In summary, the conversation discusses how to measure the intensity of light from a point source at different distances. The formula I1 x d12=I2 x d22 is used to calculate the intensity at predefined intervals, and a voltmeter and CdS cell are used to verify the calculations. The term "visibility" is corrected to "intensity" and the correct term for measuring the power received by a fixed area is irradiance.
  • #1
MangoOverlord
3
0
[a]1. Homework Statement [/b]
How does the distance from a point source of light affect the visibility of that light from the said source?


Homework Equations


This is a bit tricky without sub points, but here goes:

I1 x d12=I2 x d22
where:
I=intensity d2=distance per sq. unit

[c]3. The Attempt at a Solution [/b]

By using the ISL formula above, I plan to find the intensity of light at predefined intervals (i.e. every 10 cm) by substituting variables in the equation. After which, I will use a voltmeter and CdS cell to verify my calculations. I'm pretty sure I'm doing everything right, but some suggestions would be nice. :biggrin:
 
Last edited:
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  • #2
You might want to be careful defining "visibility"
What you are measuring is how the power received by a fixed area (the lightmeter) = the irradiance of the light varies with distance.
 
  • #3
did i say visibility? I meant intensity. Ty.
 
  • #4
MangoOverlord said:
I meant intensity. Ty.
intensity is the power of the source
the correct term is irradiance = power/area
 

FAQ: Inverse Square Law concerning Light

1. What is the Inverse Square Law concerning Light?

The Inverse Square Law states that the intensity of light decreases as the square of the distance from the source increases. This means that the further away an object is from a light source, the less illuminated it will be.

2. How does the Inverse Square Law apply to photography?

In photography, the Inverse Square Law helps photographers understand and control the exposure of an image by adjusting the distance and intensity of the light source. It also explains why moving a light source closer to the subject will increase the brightness of the image.

3. Does the Inverse Square Law only apply to light?

No, the Inverse Square Law can also be applied to other forms of radiation, such as sound and gravity. It states that the intensity of any type of radiation decreases in proportion to the square of the distance from the source.

4. How does the Inverse Square Law affect light measurements?

When measuring the intensity of light, the Inverse Square Law must be taken into account. This means that the distance between the light source and the measuring device will greatly affect the accuracy of the measurement. As the distance increases, the measurement will decrease exponentially.

5. Can the Inverse Square Law be applied to all light sources?

Yes, the Inverse Square Law applies to all light sources, regardless of their size or strength. It is a fundamental principle of light and radiation and is essential for understanding the behavior of light in various situations.

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