Recent content by technosaurus
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High School Does the formula t = x/v apply in special relativity?
Hello Nadeen, This is an area that fascinates me, so your post caught my eye. To deal with the formula you quoted first: "v =x/t therefore t = x/v". v represents velocity (i.e. speed in a given direction), x represents displacement, and t represents time. This is more or less the same formula as...- technosaurus
- Post #10
- Forum: Astronomy, Astrophysics, Cosmology
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Undergrad Can illuminance be converted to luminance or vice versa?
Yes, thanks for taking the trouble. If I hadn't had my gestalt moment I would still be going round in circles, so your answer would have put me out of my misery :-)- technosaurus
- Post #15
- Forum: Optics
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Undergrad Can illuminance be converted to luminance or vice versa?
Can't believe I didn't realize this before. I forgot to take Lambert's cosine law into account - the size of the area seen by an observer tends to zero as the obeserver's position approaches 90 degrees from the normal (cosine 90 = 0). Doh! So yes, it's pi and not 2 x pi.- technosaurus
- Post #13
- Forum: Optics
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Undergrad Can illuminance be converted to luminance or vice versa?
Hello, (I think I put this in the wrong place before) I know this was a couple of years ago but I hope you can clear up some confusion. You appear to be saying that the luminance emitted by a surface from a perfectly diffuse surface, in relation to the illuminance incident on that surface, can...- technosaurus
- Post #12
- Forum: Optics
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Undergrad Can illuminance be converted to luminance or vice versa?
Thanks Tom, My interpretation of this definition is that luminance is the luminous intensity from an infinitessimally small area (i.e. a point) in candelas divided by the orthagonal projection of this area. Since for a Lambertian (perfectly diffuse) surface the light is reflected through all...- technosaurus
- Post #11
- Forum: Optics
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Undergrad Can illuminance be converted to luminance or vice versa?
Hello, I know this was a couple of years ago but I hope you can clear up some confusion. You appear to be saying that the luminance emitted by a surface from a perfectly diffuse surface, in relation to the illuminance incident on that surface, can be defined as follows: luminance = incident...- technosaurus
- Post #9
- Forum: Optics