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7 votes

Difference between deviation of ray and wavefront

In a homogeneous medium a wavefront is at right angles to a ray. In this problem the medium is inhomogeneous so you should not necessarily expect a ray and wavefront to be at right angles to one ...
Farcher's user avatar
  • 96.3k
6 votes

How do parallel reflected rays meet to form image at infinity? If they never meet then how is image formed?

You are correct that parallel rays never meet. Saying "the image is formed at infinity" is a loose way to say that the image distance $d_i$ approaches infinity as the object distance $d_o$ ...
J. Murray's user avatar
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4 votes

How do parallel reflected rays meet to form image at infinity? If they never meet then how is image formed?

Not just in optics, but more generally in physics, the phrase "at infinity" has to be understood in a special way. This is because infinity is itself a special mathematical term. In the case ...
Andrew Steane's user avatar
4 votes

How do parallel reflected rays meet to form image at infinity? If they never meet then how is image formed?

It is indeed not possible to form an image when the object is in the focus plane of a lens. Normally, a lens maps point in a plane to other points in according the lens equation: $$\frac{1}{d_o}+\frac{...
AccidentalTaylorExpansion's user avatar
3 votes
Accepted

Is there a way to determine whether what I see is a source of light, a real image, or a virtual image?

In principle, there is no difference between photons traveling from an object through the air and photons traveling through an optical setup. Photons are photons. That being said, it is very ...
Cort Ammon's user avatar
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1 vote
Accepted

Why total reflection happens at only 1 angle?

(1) Reflection is always at the same angle as the incident angle. Snell's law doesn't hold for reflection. (2) Snell's law gives the critical angle above which total reflection, i.e., no refraction, ...
freecharly's user avatar
  • 16.2k
1 vote
Accepted

Formula for power of a lens submerged in a medium

When the power of a single lens is defined as $P=\frac{1}{f}$, a quick modification of the lensmaker's equation for thin lenses yields the result you are asking about: $$P=\frac{1}{f}=\frac{n_2-n_1}{...
kneez's user avatar
  • 81

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