Which of the following U. S. earthquakes was the most powerful? Virginia, December 2003, magnitude of 4.5 Kentucky, July 1908, magnitude of 5.1 Illinois, January 2006, magnitude of 3.6 Washington, February 2001, magnitude of 6.8

Washington, February 2001, magnitude of 6.8 would be your answer

Explanation: The 40-second quake, calibrated at a magnitude of 6.8 on the revised Richter Scale, injures an estimated 200 persons in the region, and is cited as the cause of a fatal heart attack in Burien. Hardest hit structures are located in Olympia, including the State Capitol, and in Seattle's historic Pioneer Square.

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.