O8: Lenses: ray diagrams Materials: Ray box, optical bench, concave lens, convex lens Initial definitions and givens: real image: an image that can be projected on a screen. Light rays actually converge there. Real images are always inverted. virtual image: rays appear to diverge from a virtual image but no rays actually pass through it, so a virtual image cannot be projected on a screen. Virtual images are always upright. converging lens: a convex (positive lens), which usually produces real images (unless the object is between the focal point and the lens). diverging lens: a concave (negative) lens, which always produces virtual images. Initial instructions and questions: 1) We will investigate images formed by positive and negative lenses. 2) You have three convex lenses in your box. Which one do you think bends the light the most? Which bends the light the least? Using parallel rays from your ray box, determine the focal length of each convex lens? 3)
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