Inverse Square Law concerning Light

AI Thread Summary
The discussion focuses on how the distance from a point light source affects light visibility, emphasizing the Inverse Square Law (ISL). The formula I1 x d12 = I2 x d22 is used to calculate light intensity at various distances. The poster plans to measure intensity at intervals using a voltmeter and a CdS cell for verification. There is a clarification regarding terminology, where "visibility" is corrected to "intensity," and the term "irradiance" is introduced as the appropriate measure of power per area. The conversation highlights the importance of precise definitions in understanding light intensity and its variation with distance.
MangoOverlord
Messages
3
Reaction score
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:
Physics news on Phys.org
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.
 
did i say visibility? I meant intensity. Ty.
 
MangoOverlord said:
I meant intensity. Ty.
intensity is the power of the source
the correct term is irradiance = power/area
 

Thread 'Rolling without slipping on a curved surface'

Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
View full post »

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »

Similar threads

Intensity of Stars and the Inverse Square Law Problem
Replies
10
Views
3K
Question about Inverse Square law and sound intensity
Replies
5
Views
3K
Investigation about the inverse square law of light radiation
Replies
8
Views
4K
Inverse Square Law: Calculating Intensity at Different Distances
Replies
2
Views
13K
I Sound pressure and inverse distance law
Replies
5
Views
2K
Oscillations and inverse square law
Replies
2
Views
2K
I How does the inverse square law apply to a focused detector?
Replies
18
Views
8K
Why Do Distant Objects Appear Dimmer Due to the Inverse Square Law?
Replies
4
Views
2K
B Why does ##F## often appear as inverse square laws such as Newtonian gravity?
Replies
11
Views
2K
Inverse Square Law HELP PLEASE
Replies
3
Views
1K

Hot Threads

Recent Insights

Back
Top