“aperture”的概念、定义、习题解题方法及翻译-物理辞典

单词	aperture
释义	aperture The effective diameter of a lens or mirror. The ratio of the effective diameter to the focal length is called the relative aperture , which is commonly known as the aperture, especially in photographic usage. The reciprocal of the relative aperture is called the focal ratio . The numerical value of the focal ratio is known as the f-number of a lens. For example, a camera lens with a 40 mm focal length and a 10 mm aperture has a relative aperture of 0.25 and a focal ratio of 4. Its f-number would be f/4, often written f4. The light-gathering power of a telescope depends on the area of the lens, i.e. it is related to the square of the aperture. However, the larger the relative aperture the greater the aberrations. In microscopy large-aperture objectives (corrected for aberrations) are preferred, since they reduce the blurring caused by diffraction of light waves
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物理辞典收录了3346条物理词条，基本涵盖了常用物理知识及物理英语单词词组的翻译及用法，是物理学习的有利工具。