Great Calculations : A Surprising Look Behind 50 Scientific Inquiries (9781633880290) by Pask Colin

Author:Pask, Colin
Language: eng
Format: epub
ISBN: 9781633880290
Publisher: Random House Digital Dist
Published: 2015-06-10T04:00:00+00:00

The second piece of information needed concerns colors. Newton used his famous prism experiment (see part 1 of book 1 of his Opticks) to show that white light, like that coming from the sun, comprises many different colored components. Furthermore, the index of refraction for materials like glass and water varies a little as the color of the light involved is changed. (This is why the glass prism separates out the colors.) Thus the light coming from the sun S in figure 9.2 is somehow split into its colored components to form the rainbow seen by the observer O.

9.2.2 Rainbow Formation

We assume a spherical raindrop and the path of rainbow-forming light in it is shown in figure 9.4. Rays from the sun refract into the raindrop and reflect at the inner surface according to the rules introduced above (the sphere is assumed to be locally plane at the points of contact so those rules may be applied). The rays then leave the raindrop by another refraction event. Figure 9.4 (a) shows how light forming the primary bow reflects once inside the raindrop, while (b) shows the mechanisms for the secondary bow involving two reflections. Since there is some transmission also at a reflection point, the light is diminished in intensity at each reflection, and thus we find that with two reflections involved, the secondary bow is less intense than the primary. From figure 9.4 (a), we see that it is the angle γ that measures the observed angle between the sun's rays and those seen by the observer.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.