Phillips, Percy · London : T. C. & E. C. Jack ; New York : Dodge Pub. Co. · leaf 28
avestarting from its focus. Wefind that the reflection trans-forms the spherical wave into aplane one. Let ACBfj, in Fig. 10,be the position which a spherical wave starting fromthe focus O of the parabola would have attained at acertain instant. Draw two radii, Of, Oj cutting theparabola at e and… … Fig, 10 *& w w Fig. 11. reached k and g respectively. In the same way all thesecondary wavelets will have reached the straight fineADB and therefore this represents the section of thereflected wave-front. Reflection of Sound-wave at a Parabolic Mirror.—R. W. Wood has also shown the reflection…
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