天同師兄,有倨緊急問題

用戶2457

2011-04-18 2:33 am

想請問infinity 既image 係virtual 定係real?

更新1:

我咁問係因為,望遠鏡個image form係infinity 最後又form左係我地視網膜,咁照計係real,但係放大鏡都係最後又form左係我地視網膜,但係佢image係virtual

回答 (1)

天同

2011-04-18 6:03 am

✔ 最佳答案

The point is that any image, either it is real or virtual, could be seen by your eyes. If the image could not be seen by whatever way, it would not be said as an image.

Hence, whether the image at at infinity is real or virtual is unimportant. As long as it is an image, it can be observed by human eyes.

In reality, image produced at large distance from the lens can be regarded as image located more or less at infinity. Hence, you may regard an image formed by a magnification glass (a simple convex lens) is virtual if the object is placed close to the focus of the lens. Similar argument could be applied to the case of a telescope.

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