Renewable energy comes from a source that is not reduced when it is used. The sun, for example, continues to have the same amount of energy whether that energy is turned into electrical energy or not. In contrast, the supply of coal decreases when it is turned into electrical energy. The primary types of renewable energy in the United States are solar, wind, biomass, hydropower, and geothermal. The amount of energy supplied by each type of renewable energy from 2006 to 2016 is summarized in Figure 1, which also includes supply projections for 2017 and 2018. During which time interval did hydropower energy production increase? Question 4 options: 2009-2010 2010-2011
2011-2012
2012-2013

unlike poles attract

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.

technology is the application of the knowledge gained by science.