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APPENDIX
                                                                                               I









                       ANSWER KEY TO PROBLEM SETS















                       Chapter 1

                       (2) For pancreatic ascinar cells, cell diameter  10  m, nucleus diameter  5  m; secre-
                       tory granule  1  m. (3) The field stop diaphragm is used to limit the area of illumina-
                       tion in the specimen to protect the specimen and reduce the amount of scattered light
                       reaching the eye or detector. Opening the diaphragm too far causes unnecessary expo-
                       sure and reduces contrast; closing the diaphragm too far masks field of view. Neither
                       operation changes the intensity of light in the image to a significant extent. The con-
                       denser diaphragm likewise has an optimum setting, typically allowing transmission
                       through 70% of the back aperture of the objective lens. A Bertrand lens is required to
                       make the adjustment. If opened too far, excess light fogs the image; if stopped down,
                       contrast is improved, but spatial resolution is compromised. The 70% position offers a
                       good compromise between image contrast and resolution. Reduction of image bright-
                       ness should be made by reducing the voltage of the power supply or by inserting a neu-
                       tral density filter in the optical path.



                       Chapter 2

                       (1) The principal complementary color pairs are red-cyan; yellow-blue; green-magenta.


                       Chapter 4

                       (1a) No, the object is located slightly outside the focal length of the objective. To pro-
                       duce a magnified real image, the object is located between 1 and 2 focal lengths.
                       (1b) No, the intermediate image is located slightly inside the focal length of the ocular
                       as is required to form a magnified virtual image. (1c) The eye-brain system perceives a




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