Diffusion by reflection from a rough surface is described in this chapter. Light can also be diffused by refraction. Describe how this occurs in a specific situation, such as light interacting with crushed ice.
Week one day 1 Chapter 19: electric charge 1. The effects of electric charge were first observed as static electricity: ● after being rubbed on a piece of fur, an amber rod acquires a charge and can attract small objects. 2. The phenomena: ● silk on glass - glass positive ● Fur on rubber: rubber negative Benjamin Franklin name it for +/-. He know it is two opposite charge. ● The concept: unlike charges attract. Like charges repel. 3. More facts of charges ● 2 types of charges ● Electric charge is always conserved - Charge is not created, only transfer,exchange ● Origin of charges - Electrons and protons - Charges quantized (e) : - Electron= -e. - Proton = +e ● e=1.6*10^-19C ● SI unit: C=Coulomb 4. How it works ● Polarization & attraction ● Some materials can become polarized. -Their atoms rotate in response to an external charge. - This is how a charged object can attract a neutral one. 5. 19.2 insulators VS conductors ● Insulators: woods, rubber, styrofoam, most ceramics. ● Conductors: copper, gold,exotic ceramics .. sometimes called metals. ● Insulators: charges cannot move Will usually be evenly spread throughout object. ● conductors : charges free to move ● Semiconductors: in between . e.g: silicon & germanium 6. Charging by conduction : A charged object (rod) is placed in contact with another objects (phere ). Some electrons on t