Image formation and ray diagrams

[fellowsk]

Ok, a lens is held upright with a piece of clay. In front of it is a bulb, and behind it is a screen at the location of the image of the bulb. Now, what would happen to the image if the top half of the lens were covered by a mask? And what if the mask had a small hole in the center and were placed in front of the lens? This is an extra credit lab, and I have been trying to figure it all out on my own, but this question I really have no idea.

[Parth Dave]

why dont you test it and see?

[fellowsk]

I don't have the equipment to test it and experiment.

[fellowsk]

See, I keep thinking that you would not be able to see the top half of the image. But the light rays from the top half of the object could strike the bottom part of the convex lens and still form the image. The same reasoning goes for covering the lens with a mask with a hole in it. Or would you only see the middle of the lens? Help!