Abstract
We have noted that according to Maxwell’s theory of electromagnetism, light is nothing but a visible electromagnetic (EM) wave that has a frequency in the narrow range ∼ 4 ×1014 Hz to ∼ 7 ×1014 Hz. The corresponding range of wavelengths is 4,000–7,000 { Å}. Furthermore, EM waves are produced and emitted by accelerating electric charge. There are two interesting questions that immediately confront us: (1) We accept the premise that animal eyes evolved so as to be sensitive to sunlight. Still, what characteristics of animal eyes makes them sensitive to this particular narrow range of frequencies? (2) What are the physical characteristics of the sun that causes sunlight to be concentrated in a particular range of frequencies?
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Notes
- 1.
The following website (12-29-2010) enables you to see the emission spectrum of elements shown in the periodic table. http://chemistry.bd.psu.edu/jircitano/periodic4.html.
- 2.
As an example, the set of numbers, {1, 2, 4}, can be represented by 2n − 1 or by \([n(n - 1)/2 + 1]\), where n = 1, 2, and 3, respectively.
- 3.
The term “in principle” means that one merely had to solve the mathematical equations and one would find that the theory would be confirmed by experiment. In practice, there are many phenomena that require the solution of equations that are too difficult and complicated to solve, so that the theory cannot be tested. However, unsolvability does not imply that the equations and the theory that they represent are incorrect.
- 4.
This statement is likely to strike the uninitiated reader as being preposterous since it implies that Physics cannot answer questions that are fundamental to its own ultimate purpose. Originally, Physics provided us with two components for describing the behavior of the physical world:
-
1.
Accounting for our observations
-
2.
Providing us with a picture as to what systems look like. With respect to the solar system, the Laws of Physics allow us to predict where we will find a planet at any instant of time; and, we can draw pictures and produce cinema simulations of a planet in orbit
According to Quantum Theory, we have to give up the second component. We cannot predict where an electron will be nor can we draw any picture describing its motion. The electron cannot be described in terms of anything we have observed with our eyes. The electron is what it is, unknowable in our terms. There is an interesting comparison in the Torah, where it is written: Moses said to God, “Suppose I go to the Israelites and say to them, ‘The God of your fathers has sent me to you,’ and they ask me, ‘What is his name?’ Then what shall I tell them?” God said to Moses, “I AM WHO I AM”. This is what you are to say to the Israelites: ‘I AM has sent me to you.’
The reader might ask how a discipline can discover by reasoning internal unto itself its own limitations? A full discussion of this issue is beyond the scope of this text. My best recommendation is that you view the video of Richard Feynman lecturing on Probability and Uncertainty, The Quantum Mechanical View of Nature. You can see the lecture by Feynman on this website (1-12-2011):http://www.clicker.com/web/richard-feynman-the-messenger-series/Probability-and-Uncertainty:-The-Quantum-Mechanical-View-of-Nature-404149/. The lecture is contained in the book by Richard Feynman entitled The Character of Physical Law [MIT Press, Cambridge, MA, 1967].
-
1.
- 5.
The numbers to the right of the figure correspond to the quantum numbers n = 1, 2, and 3. You see one probability density for n = 1, two for n = 2, and three for n = 3. Absent are two others for n = 2 and five others for n = 3. Thus, in the place of Bohr’s one state for each n, there is one state for n = 1, four for n = 2, and nine for n = 3.
- 6.
The theory provides us with equations that need to be solved to calculate the material properties. In practice, these equations are so complex that they can be solved only approximately. However, any discrepancy between calculated values and observed values is accountable by the approximation of the calculation and not any shortcomings of the theory.
- 7.
See Sect. 14.12 for more details.
- 8.
Note that typically the average time for a atomic transition is on the order of 10 nanoseconds (10 − 8 s).
- 9.
See the website http://hyperphysics.phy-astr.gsu.edu/hbase/optmod/qualig.html for more details about lasers.
- 10.
See Chap. 7 for details.
- 11.
Regarding Fig. 6.21 you can see the Black Body curve for any chosen temperature as well as the corresponding color of the spectrum using the following physlet: (12-29-2010): http://ephysics.physics.ucla.edu/physlets/eblackbody.htm.
- 12.
The interested reader can carefully check from the curves that the wavelength at the peaks is inversely proportional to the absolute temperature.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
Copyright information
© 2012 Springer Science+Business Media, LLC
About this chapter
Cite this chapter
Gunther, L. (2012). The Atom as a Source of Light. In: The Physics of Music and Color. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-0557-3_6
Download citation
DOI: https://doi.org/10.1007/978-1-4614-0557-3_6
Published:
Publisher Name: Springer, New York, NY
Print ISBN: 978-1-4614-0556-6
Online ISBN: 978-1-4614-0557-3
eBook Packages: Physics and AstronomyPhysics and Astronomy (R0)