To correct hyperopia (farsightedness), convex lenses are prescribed. If a senior citizen can read a newspaper only when he holds it no closer than 50 cm away, what focal length of lens should be prescribed so he can read when he holds the newspaper 25 cm away?
Answer to relevant QuestionsA biology student wants to examine a bug at a magnification of + 5.00 (a) The lens should be (1) convex, (2) concave, (3) flat. Explain. (b) If the bug is 5.00 cm from the lens, what is the focal length of the lens? Show that for thin lenses that have focal lengths f1 and f2 and are in contact, the effective focal length (f) is given by A biconvex lens is made of glass whose index of refraction is 1.6. The lens has a radius of curvature of 30 cm for one surface and 40 cm for the other. Calculate the focal length of this lens as used in air and under water. Two lenses, each having a power of + 10 D, are placed 20 cm apart along the same axis. If an object is 60 cm from the first lens (not in between the lenses), where is the final image relative to the first lens, and what are ...(a) Derive a relationship that gives the locations of the minima in a Young’s double-slit experiment. What is the distance between adjacent minima? (b) For a third-order minimum (the third side dark position from the ...
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