Calculate the intensity of a solid object made up of point light sources?

  • Thread starter Thread starter ericwithakay
  • Start date Start date
  • Tags Tags
    Intensity
AI Thread Summary
To calculate light intensity from a solid object made of point light sources, integration is necessary to account for the luminosity of differential elements. Each element, such as area or volume, contributes to the total luminosity observed at a specific point, following the inverse square law. By subdividing the object into small differential areas and integrating, one can determine the total luminosity received at a given location. This approach aligns with the Gaussian sphere concept mentioned. Overall, solving this problem involves complex integration to accurately assess light intensity.
ericwithakay
Messages
2
Reaction score
0
So I understand that to calculate the intensity a distance d away from a light-bulb you would treat the light-bulb as a point source and do a gaussian-sphere-type-of-thing to figure out the intensity at the desired location.

My problem involves a solid object made up of "point" light sources and I'm wondering whether I need integration to be able to solve the problem.

Any advice would be greatly appreciated.

Thanks

-E
 
Physics news on Phys.org
Yeah, sounds like you'll need to integrate. I think you could get this with a little more work.
You want your differential element of your body, be it area, volume, what have you, to have some measure of luminosity. So say you have the unit circle that has luminosity m per unit area. Then you subdivide your circle into little differential elements dA. Then for each dA the luminosity you observe at point (p,q) is (m/[(x-p)^2+(y-q)^2])dA lumens from each dA or whatever measure of light intensity you are using (that's the Guassian sphere thing you mentioned). That is, the luminosity falls according to the inverse square of the distance. If you integrate over the area of the circle you get the total luminosity an observer at (p,q) gets. Not an easy integral though.
 
Consider an extremely long and perfectly calibrated scale. A car with a mass of 1000 kg is placed on it, and the scale registers this weight accurately. Now, suppose the car begins to move, reaching very high speeds. Neglecting air resistance and rolling friction, if the car attains, for example, a velocity of 500 km/h, will the scale still indicate a weight corresponding to 1000 kg, or will the measured value decrease as a result of the motion? In a second scenario, imagine a person with a...
Thread 'Gauss' law seems to imply instantaneous electric field propagation'
Imagine a charged sphere at the origin connected through an open switch to a vertical grounded wire. We wish to find an expression for the horizontal component of the electric field at a distance ##\mathbf{r}## from the sphere as it discharges. By using the Lorenz gauge condition: $$\nabla \cdot \mathbf{A} + \frac{1}{c^2}\frac{\partial \phi}{\partial t}=0\tag{1}$$ we find the following retarded solutions to the Maxwell equations If we assume that...
Dear all, in an encounter of an infamous claim by Gerlich and Tscheuschner that the Greenhouse effect is inconsistent with the 2nd law of thermodynamics I came to a simple thought experiment which I wanted to share with you to check my understanding and brush up my knowledge. The thought experiment I tried to calculate through is as follows. I have a sphere (1) with radius ##r##, acting like a black body at a temperature of exactly ##T_1 = 500 K##. With Stefan-Boltzmann you can calculate...
Back
Top