一條簡單物理問題！
2008-08-28 2:34 am
1. Suppose the shortest distance Peter can see clearly without wearing spectacles is 40 cm. If Peter is wearing the spectacles and the object is placed 25 cm in front of his lenses, explain whether he can see the object clearly. (2 marks)
回答 (1)
2008-08-28 4:36 am
✔ 最佳答案
The image of the object formed by the spectacles has to be located at 40 cm in oder for Peter to see it clearly. Since the image is farther away from the lens (spectales) than the object, the lens is a convex lens. In other wrods, Peter is suffering from long-sightedness.The focal length of the lens of his spectacles can be found as follows using the thin lens equation:
1/25 +1/(-40) = 1/f, where f is the focal length of the lens
solving for f gives f = 67 cm
收錄日期: 2021-04-29 17:28:38
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080827000051KK02466