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Quote from: hamdani yusuf on 20/03/2022 22:24:44Quote from: Bored chemist on 20/03/2022 13:11:00Diffraction stops it being scientific.How does a curved surface create diffraction? I wasn't aware that anyone had said that it did.
Quote from: Bored chemist on 20/03/2022 13:11:00Diffraction stops it being scientific.How does a curved surface create diffraction?
Diffraction stops it being scientific.
Quote from: hamdani yusuf on 20/03/2022 10:09:21Quote from: Bored chemist on 20/03/2022 09:44:24It would be a math problem if the mirror was a polygon.Why does it stop being math problem when the number of sides of the polygon is increased toward infinity, i. e. becomes a circle? Because it stops working.If a beam of light hits a curved surface, it's no longer a beam.
Quote from: Bored chemist on 20/03/2022 09:44:24It would be a math problem if the mirror was a polygon.Why does it stop being math problem when the number of sides of the polygon is increased toward infinity, i. e. becomes a circle?
It would be a math problem if the mirror was a polygon.
How should I interpret this?
What prevents a mathematical ray from having infinitesimally narrow width?
" How many times would a light ray be reflected inside a circular mirror?"Once, after that, it's no longer a ray.
Will it stop being reflected?
Quote from: hamdani yusuf on 05/05/2022 05:16:15Will it stop being reflected?In that question you use the word "it".to what does the word refer?You can't be referring to the light ray- because that no longer exists.
Something that doesn't exist can't be reflected.
Quote from: hamdani yusuf on 06/05/2022 11:01:51Something that doesn't exist can't be reflected.So why did you ask if it was?Quote from: hamdani yusuf on 05/05/2022 05:16:15Will it stop being reflected?
Just draw what happens to a fairly narrow beam of light when it enters a hole in a hollow spherical mirror and is reflected.How big is when it has crossed the sphere twice (i.e. through and back)?
It depends on the width of the light beam and the curvature of the mirror
Caution, optics is not my area of expertise(assuming I have any!). I would imagine a narrow beam through a small hole would cause diffraction about the edge of said hole.
Quote from: hamdani yusuf on 09/05/2022 23:31:35It depends on the width of the light beam and the curvature of the mirrorOK for a beam of width W and a mirror of radius R
Quote from: Bored chemist on 10/05/2022 08:38:31Quote from: hamdani yusuf on 09/05/2022 23:31:35It depends on the width of the light beam and the curvature of the mirrorOK for a beam of width W and a mirror of radius RSay W= 0.1 mm, while R=10 m
If you shine a beam of light at a concave mirror it is brought to a focus.The focal length is half the radius of curvature.So the distance from the focal point (F) to the point (P) where the light strikes the mirror is half the radius of the sphere and, the distance to the other side of the sphere (G) is 3 times as big. (It's 3/4 times the diameter as opposed to 1/4 times the diameter)That means the edges of the light form (roughly) two similar triangles , one 3 times as big as the other .So the width of the beam when it strikes G is about 3 times W.Now that (divergent) light beam is bounced back across the mirror.If it was a parallel beam then the same thing would happen to it as happened to the original beam. It would be 3 times as big when it hit the mirror for a third time.So it would be 9 times W.But it was already diverging after the first reflection, so the width will be even bigger.But to a rough approximation, the width of the beam, after n reflections is (at least) 3^n times bigger than the original beam.
Say W= 0.1 mm, while R=10 m