(2009? Fuzhou) Application of Wavelet in the Experiment of Exploring Convex Lens Imaging (L) The experiment requires that the centers of candle flame, convex lens and light screen are approximately at the same height.
(1) The centers of the candle flame, convex lens and light screen are about the same height, in order to make the image in the center of the light screen.
So the answer is: the center of the screen.
(2) The convex lens is facing the parallel light, and the smallest and brightest light spot appears on the screen, which is the focus, and the distance from the focus to the optical center of the convex lens is the focal length.
So the focal length of this convex lens is: f = 60 cm-50 cm = 10 cm.
So the answer is: 10.