Afrenkel defect in a crystal is formed when an atom leaves a normal site and moves to an interstitial site (a space inside the crystal). the energy of formation of the defect is e suppose a crystal has n normal sites and n' interstitial sites (n' is usually similar to n.) (a) (i) show that the multiplicity q of the state in which the crystal has n frenkel defects is given by n'n! ω- (n n)(nn)n [2 marks] (11 write down an expression for the entropy s as a function of n [2 marks] equilibrium is (b) show that, for n < < n, n', the number of frenkel defects at (nn exp-s/2kt) [4 marks] (c) explain briefly why the equilibrium number of vacancies differs from zero when the crystal is at temperature t greater than zero

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.

statement #3 on andre"s list is false.

you can cut your hand off if your not