Last month I asked here whether there's a consensus about Van Flandern's speculations about the speed of gravity. I quickly learned that he's not well-regarded. Fine. I was hoping to be able to get something out of Steve Carlip's explanation for how GR explains the apparent almost...
I'm interested in the prehistory of the history of relativity. In this
history the nature of light and the ether comes in. One phenomenon that
was debated in this context was stellar aberration: that the positions
of the stars in the sky change slightly, or, more precisely, the
perceived...
How does spherical aberration cause an image to appear when the object is placed at the focus?
In theory, when the object is placed at the focus, no image should appear but when i did an experiment with a concave mirror and a candle, image did appear. But the image was very very far away...
Concave mirror experiment
We did an experiment with a concave mirror
Concave mirror was placed on optics bench and a candle was placed at designated spots. A screen was used to see where the image was projected. But a strange thing happened. When the object was placed at the focal point, image...
What is the approximate difference in the points of convergence between red and blue light when using a spherical lens? Is it negligible (i.e. less than a millimeter)? Is it a specific distance or is it a function of a separate variable?
Essentially, I'm curious as to why the focal length of a lens with red light is the closest to the focal length in white light.
MY ATTEMPTED ANSWER:
According to the lens-maker's equation, the focal length of a lens depends on the index of refraction of the lens material, which in turn is...
I was thinking of something and maybe somebody can explain...
If rain is coming straight down at a rate of 4 meters/second and I'm walking along at a rate of 3 meters/second then the rain is hitting me at an angle at a rate of 5 meters/second. So, then why doesn't the same sort of reasoning...