. Problems in physics. Derived from military situations and experience . cal panoramic sight shown in Figure 14 (a), which has two right angle prismsand the objective prism turned for a back sight? 82. Will the image be perverted? 83. If the objective prism is turned around so that observer looks straight ahead, as in Figure 14 (b), will the image be erect? 84. Will it be perverted? 85. What will be the position of the image for an intermediate position of the objective prism? 86. The system actually employed in the panoramic sight is shown in Figure 14 (c). It is to eliminate rotation of the
. Problems in physics. Derived from military situations and experience . cal panoramic sight shown in Figure 14 (a), which has two right angle prismsand the objective prism turned for a back sight? 82. Will the image be perverted? 83. If the objective prism is turned around so that observer looks straight ahead, as in Figure 14 (b), will the image be erect? 84. Will it be perverted? 85. What will be the position of the image for an intermediate position of the objective prism? 86. The system actually employed in the panoramic sight is shown in Figure 14 (c). It is to eliminate rotation of the imagethat the rotating prism is added, which is so geared to theobjective prism that it rotates at half the angular velocityof the objective prism. If the two ordinary right angleprisms are retained, will the image now be perverted? 87. How will the substitution of a roof prism for the lower right angle prism remedy this difficulty? Try to picture to your-self the manner in which the rotation of the rotating prismkeeps the image erect as the objective prism is ?^ OPTICAL SYSTEMS i53 THE RANGE FINDER 88. Why are penta prisms instead of right angle prisms used at the ends of the base line of the range finder? 89. If an ordinary right angle prism were used instead of the penta prism, through how great an angle would it have to rotatein order to displace the reflected ray 1 second? 90. If the square faces of the prism are 2x2 inches, and one of the edges is held stationary, how far would the other edges haveto move in order to permit this much rotation? 91. In an instrument of the type which shows one half of the field inverted, do both halves of the range finder have the samenumber of reflections? 92. With the sharp dividing line employed in the range finder the eye can detect a lack of coincidence between two pointssubtending an angle of 15 seconds in the apparent field. Towhat actual angle in the real field does this correspond, ifthe magnification is fifteen? 93. If th
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