of diameter 2/d
A thin lens has focal length f, and its aperture has diameter d. It forms an image of intensity I. If the central part of the aperture, of diameter 2/d, is blocked by an opaque paper, the focal length of the lens and the intensity of image will become
17
Nov
A thin lens has focal length f, and its aperture has diameter d. It forms an image of intensity I. If the central part of the aperture, of diameter 2/d, is blocked by an opaque paper, the focal length of the lens and the intensity of image will become A thin lens has focal length [...]