Questions tagged [light]

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1answer
158 views

Was it suspected that the speed of electricity was equal to the speed of light?

Was it believed early on that signals sent via wire moved at exactly the speed of light or simply very fast? Who was the first to estimate the speed? EDIT: Given that they move at less than the ...
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1answer
86 views

What was the original reason physicists first believed that light must follow a geodesic?

Context: One of the key reasons Einstein first suspected space is curved by mass is due to the falling elevator thought experiment. This experiment implies that mass must curve the path of a light ray....
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1answer
84 views

What was Isaac Newton's contribution to optics?

What was Isaac Newton's contribution to optics? I know that he believed in the corpuscular theory of light. Did he know about the laws of reflection ad refraction?
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1answer
105 views

Reference request concerning an alleged Jewish contribution to the early theory of light refraction, and to the first geometry textbook in Europe

Page 50 of the book Gustav Karpeles: A Sketch of Jewish History. Translated from the German [by an anonymous translator]. The Jewish Publication Society of America. 1897. contains the following ...
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0answers
171 views

Speed of light in aether

I've been recently reading about the famous Michelson-Morley experimental attempt to detect the Earth motion with respect to the aether. According to Wikipedia, Michelson initially made a mistake ...
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3answers
496 views

“Tension” between Electromagnetism and Newton's laws

When talking about the inconsistencies in physics that led up to Einstein's discovery of relativity today's professors always say that Maxwell's discovery of the constant speed of light $c$ created a ...
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0answers
57 views

Why did Arago in 1810 not assume that the refraction angle is independant on the light speed?

I am readying on Arago's experiment of 1810 in a book on the history of physics. The author writes that Arago conducted the experiment assuming that light consisted of particles and that faster light ...
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1answer
256 views

Why was the question of the nature of light limited to the wave theory or the particle one ?

The question is in the title. I'm obviously refering to the 17/18 th century somewhere around this era.
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2answers
334 views

How Einstein got the first idea for special relativity?

I am reading Big Bang by Simon Singh. Here is the short story (as I understood it): Einstein gets a contradiction by assuming that 1- The speed of light $c$ is constant with respect the ether. 2- ...
12
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2answers
499 views

How did people explain color before the splitting of white light was discovered?

We know that a body is red because it absorbs (visible) light of all wavelengths except that for the red. But before Newton showed that white light was actually made up of seven colors how did people ...
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0answers
314 views

What was the need for Lorentz transformation in pre-relativity period?

Why was it necessary for the velocity of light to be invariant between different inertial frames and hence what was the need for Lorentz transformation when it was believed that velocity of light was ...
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0answers
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Why were light bulbs traditionally marketed based on power consumption rather than light output?

Historically, incandestent light bulbs were marketed primarily by their power consumption in watt. I don't know if light output in lumen was specified at all. I'm not aware of any other electrical ...
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1answer
2k views

How exactly did Hertz's experiments confirm Maxwell's theory?

Hertz's experiments are said to have proven Maxwell's theory correct, but how exactly did his experiment do this?
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1answer
110 views

Why is the Michelson–Morley experiment so much more famous than its rivals?

The first paragraph of Albert Einstein's paper On the Electrodynamics of Moving Bodies, written in 1905, mentions the failure of attempts to detect the earth's motion through the luminiferous aether. ...
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2answers
2k views

How did Maxwell conclude that light is an electromagnetic wave?

This is a copy of a question I just asked at Physics Stack Exchange. From reading the text on the related questions, it seems that Maxwell equated light with the carrier of electromagnetic force just ...
2
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1answer
628 views

How did we come to the conclusion that light moves as fast as it does?

Scientist predict that light moves 3x108 m/s in a vacuum. Then, when light hits a medium like air, it goes into a medium with a different index and travels slower (I believe it indexes at 1.007 in air)...
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2answers
493 views

What were theories for why and how we see things?

That we see things seems unquestionably obvious. But, when I try to think about how, I find it as a mystery. The conventional answer nowadays to this question revolves around absorption and ...
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1answer
166 views

What theories preceded the wave, particles and duality models of light?

Currently, the wave-particle duality model for light is the accepted model. From HyperPhysics: The evidence for the description of light as waves was well established at the turn of the century ...