Irradiance at a point on a surface

In summary, the formula for irradiance on a sphere is flux divided by 4π times the radius squared. This gives the amount of energy per unit of time that passes through a specific area on the sphere. The dimensions of the point are not relevant, except when an infinitesimal surface is drawn around it to determine the value at that point.
  • #1
Pilpellon
4
0
My book states that "irradiance at a point on the outer sphere is less than irradiance at a point on the inner sphere."

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The formula is simple, it's flux/area. So in case of a sphere its flux/4π*r^2.
But my question is what exactly does this formula give? does it give the total flux that arrives on a point on the sphere? If so, what are the dimensions of that point? The book totally confused me on that part.
 
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  • #2
power or flux (energy/time) per area = irradiance
It gives you how much energy per unit of time passes through some area.
No point is concerned, except for if around that point you draw an infinitesimal surface. So you can determine its value at those points.
 

Related to Irradiance at a point on a surface

What is irradiance at a point on a surface?

Irradiance at a point on a surface refers to the amount of radiant energy that is incident on that specific point from all directions. It is measured in watts per square meter (W/m²) and is an important concept in fields such as physics, meteorology, and solar energy.

How is irradiance at a point on a surface calculated?

Irradiance at a point on a surface can be calculated by dividing the total radiant energy incident on that point by the surface area over which it is distributed. This can be expressed as E = P/A, where E is the irradiance, P is the radiant power, and A is the surface area.

What factors affect the irradiance at a point on a surface?

The irradiance at a point on a surface can be affected by several factors, including the distance from the radiation source, the angle of incidence, and the surface's orientation and reflectivity. Other factors such as atmospheric conditions and the presence of obstructions can also impact irradiance.

Why is irradiance at a point on a surface important?

Irradiance at a point on a surface is important because it provides information about the amount of radiant energy that is available for various processes, such as photosynthesis, solar power generation, and heating. It is also a key factor in understanding climate and weather patterns.

How is irradiance at a point on a surface measured?

Irradiance at a point on a surface can be measured using instruments such as radiometers, pyranometers, and photometers. These devices use sensors to detect and measure the amount of radiant energy at a specific point and convert it into an electrical signal that can be recorded and analyzed.

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