why flat mirror dont hav updown reflections?

Answer 1

I think you are asking this question: "Although it is obvious that a flat mirror reverses left and right, it does not seem to reverse up and down; but how does a mirror know the difference? So why are up and down not reversed?"

Actually, the reversal is as much psychological as physical. You move your left hand, but your iright hand moves. Now imagine that you are a mutant, with eyes vertically instead of horizontally disposed on your face. You move your "upper" hand, and your image's "lower" hand appears to move. Your perceptions of left/right and up/down are tied to the map you have of your own body. You automatically refer other objects, like the capital letter "F," to that same orientation. Therefore the mirror-reflected "F" seems to be switched left-right, but not up-down.

The mechanism of mirror reflection can be put in a way which seems much more symmetric. Assume a "coordinate system"--which is just three arrows, one pointing to your right, one pointing up, one pointing toward the mirror. You can make such a thing by taping together three pencils. Now hold it in front of the mirror with the forward facing the mirror. Notice: the reflection of the right arrow still points to your (not your reflection's) right, the reflection of the upward pointing arrow still points up. But the reflection of the outward pointing arrow n ow points back at you! That is the essential difference, and it is perfectly symmetric with respect to the face of the mirror.

Answer 2

Yes, flat mirror can produce upside-down reflections.

A single flat mirror is often used in astronomical telescope such as a Refractor to change the direction of the light path so that the viewing angle is more comfortable and it creates an erected image. However, the image is still a "mirror image" (reversed left to right). The 45 degree image erector can be made using a mirror or a prism.

The reason we do not see ourselves turned upside down when we look at the mirror is because it is a "locked" system. Inorder for us to see ourselves, we need to be looking at the mirror within the perpendicular plane. In the perpendicular plane, the light rays are reflected back directly at us or more accurately to our eyes. At the eye-level, the angle of Incident = angle of Reflection = 90 degrees. When we look at the eye-level, we will see our eyes. When we look down, we see our feet. The image is therefore not upside-down but just a "mirror image".

However, if you place the mirror on the ground, and peek downwards while standing on the mirror, you will see an inverted image of yourself. Enjoy!

Answer 3

mirror just change the direction of the light. they don't flip it around.

imagin a mirror on a wall. The mirror is facing south. You are standing south of the mirror and facing it , i.e. you are facing north.

Now imagine, photons that were flowing north toward the mirror are now bounced off and are flowing south so that you can see them.

Therefore everything is where it should be -your head and body and arms are all as they were as if someone were standing south of you and looking at you from your rear. That's it... That person will see your backside, back of head, left arm, right arm etc. Then they can peer past you to your image in the mirror and everything is the same except that they can now see the front instead of the back.

So nothing is actually swapped left for right or up for down. Just front to back.

Our minds, trying to make sense of this will substitute left and right.

Answer 4

Inverted reflections only happen beyond the focal point of a concave mirror. Since a flat mirror has no focal point (or has a "virtual" one at infinity), you don't get an inversion.

Answer 5

Because light is reflected in the same path as the entry.