The paper, for example, is not perfectly flat but has a roughness on some length scale as shown in the picture. Some parts of it thus are always reflecting the light into your eye.

Condensed water vapor means you have small water droplets (it they're too big they fall down and we call it rain) in the atmosphers; milk means you have some emulgated grease particles in the water.

Light is scattered at those small things in all directions and the scattering of light is one topic we encounter if we look at not-so-perfect materials

Since "small"and "large"are relative values we must use the obvious natural length scale when dealing with light as our ruler and that is of course the wave length l » 1 µm. We then distinguish three cases depending on the length scale l_mat inherent to our material

l_mat << l. The extreme would be scattering at single atoms or molecules but proper nanoparticles also belong into this group. This kind of scattering is called Rayleigh scattering.
l_mat >>l. No probel, we cpovered that already. Just look at any part by itself and apply what we discussed before.
l_mat » l. Mow we have a problem. What will happen in this case is difficult to deal with and no general rules apply. This kind of scattering is called Mie scattering

Spezialzeichen

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Integral von v1 - v2

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»	ungefähr	Ñ	Napla
¹	ungleich	Ü	Doppelpfeil links
µ	proportional	ÞÜ	Beide Pfeile
v₂ ó õ v₁	Integral von v1 - v2	®	Einfachpfeil rechts
v₂ S v₁	Summe
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2. Energy

2.1 What We Need

2.1.1

The

The

s = \|q\| · n · µ

[r]	=	Wm

[s]	=	(Wm)^–1	= S/m

Some Values and Comments

Metal	Ag	Cu	Au	Al	Na	Zn	Ni	Fe	Sn	Pb	Hg
r [mWcm]	1,6	1,7	2,2	2,7	4,2	5,9	6,8	9,7	12	21	97
s = 1/r [10⁶ · W^–1cm^–1]	0.625	0.588	0,455	0.37	0.238	0.169	0.147	0.103	0.083	0.046	0.01
s = 1/r [10⁶ · W^–1m^–1]	62,5	58.8	45.5	37	23.8	16.9	14.7	10.3	8.3	4.6	1

Questionaire
Multiple Choice Fragen zu 2.1.1