First Book of Heat, Light and Optics, and Electricity, by J.L. Comstock and R.D. Hoblyn

First Book of Heat, Light and Optics, and Electricity, by J.L. Comstock and R.D. Hoblyn

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1846 edition. Excerpt: the angle which the rays of light, proceeding from their extreme parts, form when they meet at the eye. For it is plain that the half of any object will appear under a less angle than the whole, and the quarter under a less angle still. Therefore, the smaller an object is, the smaller will be the angle under which it will appear at a given distance. If, then, a mirror make the angle under which an object is seen smaller, the object itself will seem smaller than it really is. Hence the image of an object, when reflected from the convex mirror, appears smaller than the object itself. This will be understood by Fig. 37. Suppose the rays flowing from the extremities of the object A, to be reflected back to c, under the same degrees of convergence at which they strike the mirror; then, as in the plane mirror, the image D, would appear of the same size as the object A; for if the rays from A were prolonged behind Fig. 37. the mirror, they would meet at B, but forming the same angle, by reflection, that they would 107. Why does an image reflected from a convex surface appear smaller than the object? Why does the half of an object appear to the eye smaller than the whole?--108. Suppose the angles c and B, Fig. 37, are equal, will there be any difference between the size of the object and its image? do, if thus prolonged, the object seen from B, and its image from c, would appear of the same dimensions. But, instead of this, the rays from the arrow A, being rendered less convergent by reflection, are continued onward, and meet the eye under a more acute angle than at c, the angle under which they actually meet being represented at E, consequently the image of the object is shortened in proportion to the acuteness of this angle, and the object appears...
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Product details

  • Paperback | 44 pages
  • 189 x 246 x 2mm | 95g
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236613066
  • 9781236613066