lenses

[person]

how do i determine the location of the virtual image formed by placing an object between a convex lense and the focal point of that lense experimentally??

[person]

i just realized that my original post is sort of ambiguous, so here's a diagram



how would u find where the virtual image is experimentally?

all the materials u have are:
- lense
- object
- ruler
- a peice of paper (no idea how this would help)

[Delos]

I'm not physics major, but this might be solved thusly:

- place object near window during the day. This step is important, as will be seen later.
- place lens in front of object.
- hold paper behind object, and move until object's projection/shadow has cleared as much as possible. (This is what the light is needed for.)
- use ruler to measure distance.

Yes?

[person]

but its a virtual image...so no image will form

i think it might have something to do with paralax

[Delos]

I highly doubt it's paralax, since that has to do with perceived motion of distant objects relative to each other...
Perhaps looking through the lens until the image of the object clears? There are possibilities...

[person]

ive tried that, the image looks clear no matter where u are

[person]

well, found a slolution
although i dont understand how method one rlly works

Quote:

How to locate a virtual image experimentally:
Method 1, the parallax method: Point to where the image seems to be with a vertical pencil or other thin object above or below the image. Move your head from side to side, and observe the image and the pencil (not the image of the pencil). If one has more apparent motion across your field of view, it is closer. Adjust the location of the pencil until they move together, then the pencil is pointing at the object.

Method 2.Put in a convex lens and a screen to get a real image of the virtual image, then remove the lens or mirror responsible for the virtual image and find the where to put the object such that the real image will be in the same place. Then the object is where the virtual image was.