- #1
hasankamal007
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Hello Everyone!
I have a question related to the ACTUAL APPEARANCE of the virtual image/object formed when a person wears a lens.
When a lens (spectacle) is used for correction of vision to make the rays meet at retina, my book says a virtual image seems to form before the lens. This takes place in both myopia(concave) and hypermetropia(convex). But, we don't see that happen in real life?
Consider the following ray diagram in myopes where concave lens is used for correction:
http://dl.dropbox.com/u/27434897/light2.jpg
Here, in the third case, the image of object at infinity should seem to be formed at F(far point). But, we don't see that happen in real life?
That said, for a person wearing spectacles - the location of image of object should be different from the location of actual object! WEIRD! Because, we don't see that happen in real life?
If this is true, the sun(which is at infinity) would appear at far point(which is usually 1m) to a myopic person. Now, that's weird! Because then the sun would appear at 1m to a myopic person! But, we don't see that happen in real life? THAT'S A HUGE DIFFERENCE BETWEEN THE TWO LOCATIONS! ONE IS MILLIONS OF MILES AWAY AND THE OTHER IS JUST A METRE IN FRONT.
So, the actual position of the object should be significantly different from the position of the image seen by a spectacle-wearing person.
I don't understand how? It would make life difficult for spectacle-people! :)
NOTE: Though I have used myopia as an example, the difference in locations of image and actual object still would persist in case of hypermetropia(convex lens).
I believe there's something wrong in here. The theory says something, but practically things are different.
Thank you all in advance.
#HappyPhysics! :)
I have a question related to the ACTUAL APPEARANCE of the virtual image/object formed when a person wears a lens.
When a lens (spectacle) is used for correction of vision to make the rays meet at retina, my book says a virtual image seems to form before the lens. This takes place in both myopia(concave) and hypermetropia(convex). But, we don't see that happen in real life?
Consider the following ray diagram in myopes where concave lens is used for correction:
http://dl.dropbox.com/u/27434897/light2.jpg
Here, in the third case, the image of object at infinity should seem to be formed at F(far point). But, we don't see that happen in real life?
That said, for a person wearing spectacles - the location of image of object should be different from the location of actual object! WEIRD! Because, we don't see that happen in real life?
If this is true, the sun(which is at infinity) would appear at far point(which is usually 1m) to a myopic person. Now, that's weird! Because then the sun would appear at 1m to a myopic person! But, we don't see that happen in real life? THAT'S A HUGE DIFFERENCE BETWEEN THE TWO LOCATIONS! ONE IS MILLIONS OF MILES AWAY AND THE OTHER IS JUST A METRE IN FRONT.
So, the actual position of the object should be significantly different from the position of the image seen by a spectacle-wearing person.
I don't understand how? It would make life difficult for spectacle-people! :)
NOTE: Though I have used myopia as an example, the difference in locations of image and actual object still would persist in case of hypermetropia(convex lens).
I believe there's something wrong in here. The theory says something, but practically things are different.
Thank you all in advance.
#HappyPhysics! :)
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