 | Harvey Goodwin - Mathematics - 1849 - 588 pages
...directly upon a spherical reflector, the distance of the centre of the sphere from the principal focus is a mean proportional between the distances of the conjugate foci from the same point. Let BAB' be the spherical reflector, O its centre, Q the focus of incidence, QOA the axis... | |
 | Natural philosophy - 1850 - 124 pages
...or converging pencils are directly incident on a spherical reflector, the principal focal distance is a mean proportional between the distances of the conjugate foci from the principal focus ; or the distance of the focus of the reflected rays from the principal focus is a third proportional... | |
 | London univ - 1852 - 358 pages
...directly upon a spherical reflector, the distance of the centre of the sphere from the principal focus is a mean proportional between the distances of the conjugate foci from the same point. 7. At what angle must two mirrors be inclined so that a ray incident parallel to one of... | |
 | Henry Latham - 1857 - 390 pages
...a spherical reflector; shew that the distance of the centre of the sphere from the principal focus is a mean proportional between the distances of the conjugate foci from the same point. Trace the changes in the position and appearance of the image as an object approaches the... | |
 | John Pringle Nichol - Physics - 1860 - 942 pages
...immediately to deduce many of the results just given, and in concentrating them into one, is the following. The focal length is a mean proportional between the...distances of the conjugate foci from the principal focus. Taking the proportions already obtained — u — г:г — v :: u:v or u — r:u :: г — v:v we... | |
 | 1878 - 632 pages
...mirror is convex and the pencil diverging. In either case prove that the focal length of the mirror is a mean proportional between the distances of the conjugate foci from the principal focus. 3. When a ray of light passes in a perpendicular section through a prism of a refracting substance,... | |
 | 1897 - 534 pages
...jpMr. WJ BROWNE, District InsjKsctor. ' p"*' 1 . Prove that in a concave mirror the focal distance is a mean proportional between the distances of the conjugate foci from the principal focus. 10 marks. 2. (a) Explain how the velocity of sound in air has been ascertained (1) by calculation,... | |
 | Great Britain. Parliament. House of Commons - Great Britain - 1878 - 634 pages
...mirror is convex and the pencil diverging. In either case prove that the focal length of the mirror is a mean proportional between the distances of the conjugate foci from the principal focns. 3. When a ray of light passes in a perpendicular section through a prism of a refracting substance,... | |
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In either case prove that the focal length of the mirror is a mean proportional between the distances of the conjugate foci from the principal focus. 