New: Osmosis Desalination and Carnot

Light Scattering

Uri Lachish, guma science

Years ago I looked for a job and went to an interview in a company. There were two men, one young and one old. The younger man did the talking and the older man just sat there listened and said nothing.

The young man started by asking if I knew how the intensity of scattered light depend on the light frequency. I knew the answer for that and said that the intensity is proportional to the fourth power of the frequency. (See: Light Scattering).

I then made a critical mistake and asked him if he happened to know why is that.

He said: "Why What?"

I said: "Why fourth power, why not third or sixth?"

He thought for a moment and then said: "That's how it is in the formula."

To add sin to crime I said: "Yes, but what is the physical reason?"

He didn't know and I said my opinion about that.

He then stopped asking questions and took me for a tour of the company.

Later someone told me that the older man refused that I will join them.

I went to another interview, didn't repeat my mistake, and got a job in a better company, at least, better for me.

So, why is the intensity of scattered light proportional to the fourth power of the light frequency?

On the net: August, 2011.

By the author:

  1. "Osmosis Desalination and Carnot",, December 2012.
  2. "Light Scattering",, August (2011).
  3. "The Sun and the Moon a Riddle in the Sky",, July (2011).
  4. "Osmosis and thermodynamics", American Journal of Physics, Vol 75 (11), pp. 997-998, November (2007).
  5. "van't Hoff's Evidence",, October (2007).
  6. "Osmosis and Thermodynamics",, January (2007).
  7. "Expansion of an ideal gas",, December (2002).
  8. "Optimizing the Efficiency of Reverse Osmosis Seawater Desalination",, May (2002).
  9. "Boltzmann Transport Equation",, May (2002).
  10. "Energy of Seawater Desalination",, April (2000).
  11. "Avogadro's number atomic and molecular weight",, April (2000).
  12. "Vapor Pressure, Boiling and Freezing Temperatures of a Solution",, December (1998).
  13. "Osmosis Reverse Osmosis and Osmotic Pressure what they are",, February (1998).
  14. "Calculation of linear coefficients in irreversible processes by kinetic arguments", American Journal of Physics, Vol 46 (11), pp. 1163-1164, November (1978).
  15. "Derivation of some basic properties of ideal gases and solutions from processes of elastic collisions", Journal of Chemical Education, Vol 55 (6), pp. 369-371, June (1978).


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