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27 votes
Accepted

How does the mirror know what’s behind the paper?

Perhaps a diagram would help? Excuse my poor artistry: Clearly, you can see that there is a trajectory a ray can take which starts at the top of the egg, hits the mirror, and then intersects your eye....
Riley Scott Jacob's user avatar
15 votes

How does the mirror know what’s behind the paper?

The other answers are quite right, of course, but I thought it might be helpful to know the comic has a second page in which Aki Hayakawa explains how mirrors work. This prompts a rather... crude ...
Sturrum's user avatar
  • 424
7 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
  • 69.8k
5 votes

What is the apparent location of a real image formed by a lens?

The figure describes the situation, but in words, the real image will be formed on the near side of the lens (same side as observer). This was pointed out in the question. It will appear to the ...
ad2004's user avatar
  • 1,106
5 votes

How does the mirror know what’s behind the paper?

Is it not just a matter of at which angle you are and how is constructed the reflection? The reflection is just the brain trying to reconstruct the position of the object by continuing the ray of ...
Syrocco's user avatar
  • 1,108
5 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
5 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
2 votes
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
  • 16.7k
2 votes

Spherical aberration of lens

Both lenses shown have spherical aberration. For many uses, the spherical aberration of a plano convex lens is small enough not to matter. For other uses, it isn't good enough. An ideal lens would ...
mmesser314's user avatar
  • 39.5k
2 votes

What is the apparent location of a real image formed by a lens?

Real images look like real objects. Think about it: your eyes cannot distinguish, having access only to the light rays entering it, a real object from a real image. In both cases, your eyes receive ...
HTNW's user avatar
  • 4,355
1 vote
Accepted

What is a convex-concave lens?

You may want to compare to a regular convex lens, where the lens is curved outwards on both sides. Concave is like the side of a bowl you fill with soup and it stays in the bowl. If you flipped the ...
ad2004's user avatar
  • 1,106
1 vote

Spherical aberration of lens

From the picture, you can see that the biconvex lens has a second bent surface through which light is travelling through. Julie Benson and Craig Olson (and others in the optical design area) call this ...
ondas's user avatar
  • 965

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