Suppose a simple dye molecule can be modeled as having a hydrogen-like energy states with 6 electrons. initially, the electrons settle to the lowest total energy state. imagine that we illuminate this molecule with just right energy to excite the electrons from the n = 3 level to the n = 5 level. when such excited electrons decay back to their lower available energy states, photons of the same energy as the incoming photons are emitted. in addition, photons with different wavelengths can be emitted. this is known as fluorescence. (a) draw the energy-level diagram (for n = 1 to n = 6) and show how electrons are filling the energy levels before light is illuminated. (b) after the illumination, the electron’s arrangement changes in the energy diagram. draw the energy-level diagram again (for n = 1 to n = 6) and show how the electrons are filling the energy levels after the light illumination. (c) the excited electrons in (b) decays to the lower energy states. identify two transitions producing photons with longer wavelengths than the incoming photons. write your answer in this format: eph (6 →1), if the photon is generated by the electron transitioning from n = 6 to n = 1 (this is not the correct answer). (d) explain why other transitions (such as from n = 5 to n = 1) are not possible.

positive reinforcement? ?

graph slopes whilst gas cools, then it is flat whilst conensation to liquid happens, the coolong liquid then graphs as a slope when it solidifies graph is flat

latent heat

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.

a=d/t

a="triangle"v/t

explanation:

a = acceleration