• raisin_raisin
In summary, the conversation is discussing the use of steradians in Snell's law for calculating the solid angle of a refracted light source. It is suggested that for a symmetric beam, the cone angle can be used directly in Snell's law to find the new solid angle. However, for larger cone angles, more care must be taken due to asymmetry in the refracted edges. It is also noted that the steradians value cannot be used directly as the angle for Snell's law and the half-angle of the cone must be calculated in radians.
raisin_raisin
I have a light source emitting near a surface and then getting refracted. I have calculated the solid angle leaving the surface of the light I am interested in but need to find what cone this corresponds to from the emitter. Can I just stick half the solid angle into Snell's law equation even though the solid angle is in steradians and then use this answer (which presumably is in radians) as my new solid angle?

Thank you for reading, I hope I have explained what I mean (i.e basically can I use steradians in Snell's law)

If the beam is symetric then yes you can just use the cone angle with snell's law then work out the new solid angle from the new cone angle.

If the cone angle is large you might have to take more care since the different edges will be refracted different amounts and you won't have a symetric cone on the output

mgb_phys said:
If the beam is symetric then yes you can just use the cone angle with snell's law then work out the new solid angle from the new cone angle.

If the cone angle is large you might have to take more care since the different edges will be refracted different amounts and you won't have a symetric cone on the output

Thank you very much!

Uh, but you cannot just use the steradians value as the angle for Snell's Law. You do have to figure out how many radians the half-angle of the cone is.

## 1. What is the formula for calculating solid angle from light source?

The formula for calculating solid angle from light source is: Solid Angle = Light Intensity / Distance^2.

Steradians and radians are units of measurement for solid angle. Steradians are used to measure the amount of space covered by a 3D angle, while radians are used to measure the angle itself.

## 3. How is solid angle related to light intensity?

Solid angle is directly proportional to light intensity. This means that as the solid angle increases, the light intensity decreases.

## 5. What is the importance of calculating solid angle from light source?

Calculating solid angle from light source is important in various fields such as physics, astronomy, and lighting design. It allows us to understand and measure the amount of light emitted from a source and how it is distributed in a given space.

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