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Here you can see the course of a light ray through a converging lens. One always depicts three courses of light rays, all of them starting at the object point G and ending at the focal point F. The parallel ray starts parallel to the optical axis, run through G, is than refracted at the centre plane in such a way that it also runs through the focal point F of the converging lens. The centre ray runs through the centre point M of the converging lens and is thus effectively not refracted. The third light ray is the so-called focal ray which runs through the focal point F1 and whicht runs parallely to the optical axis afther the refraction. By clicking on the object point G and dragging it with your mouse you can move it up or down, making the object shorter or longer. Further you can move the object away from the lens or closer to it by clicking on G1 and dragging it with your mouse the the left or right. Why don't you try that for a bit? Try to watch what happens to the light rays and if an image point B is created. An image point is created if the light rays meet all in one point after they've passed through the lens. After you tested all that, scroll down in order to answer the question about the properties of a converging lens.
Which of the following is correct?
a) After the light rays have left the lens they move apart in different directions. An image point isn't possible.
b) After the light rays have left the lens they move apart in different directions. There will be an image point and a clear image.
c) After the light rays have left the lens they move together towards one point, as if bundled. An image point isn't possible.
d) After the light rays have left the lens they move together towards one point, as if bundled. There will be an image point and a clear image.
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