the eye has partially lost its ability of accommodation? If not, what might cause these defects of vision? . A myopic person has been using spectacles of power – .
dioptre for distant vision. During old age he also needs to use separate reading glass of power + . dioptres. Explain what may have happened.
. A person looking at a person wearing a shirt with a pattern comprising vertical and horizontal lines is able to see the vertical lines more distinctly than the horizontal ones. What is this defect due to? How is such a defect of vision corrected?
. A man with normal near point ( cm) reads a book with small print using a magnifying glass: a thin convex lens of focal length cm. (a) What is the closest and the farthest distance at which he should keep the lens from the page so that he can read the book when viewing through the magnifying glass? (b) What is the maximum and the minimum angular magnification (magnifying power) possible using the above simple microscope?
. A card sheet divided into squares each of size mm is being viewed at a distance of cm through a magnifying glass (a converging lens of focal length cm) held close to the eye. (a) What is the magnification produced by the lens? How much is the area of each square in the virtual image?
(b) What is the angular magnification (magnifying power) of the lens? (c) Is the magnification in (a) equal to the magnifying power in (b)? Explain. .
(a) At what distance should the lens be held from the figure in Exercise . in order to view the squares distinctly with the maximum possible magnifying power? (b) What is the magnification in this case? (c) Is the magnification equal to the magnifying power in this case?
Explain. . What should be the distance between the object in Exercise . and the magnifying glass if the virtual image of each square in the figure is to have an area of .