Consider a little electric dipole (like e. g., a polar molecule) with a charge +q (q > 0) a) [10 pts] determine the electric field e for points along the y-axis. briefly discuss how b) [12 pts] for your solution in part a) consider the limit l/d, i. e. a point along the located at r--d and another charge -q which is located at x - d the direction of your result for e makes sense. axis very far away: y- » define e as a function of y and d, such that e is a small quantity and expand your solution in power series up to fourth order in €. show that the units of your power series' answer are correct » for what values of y does your expansion converge? ·why doesn't your solution behave like coulomb's law, i. e., why isn't el x 1/w2 here?

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.