The document discusses various topics related to radiation safety and physics including the three key elements of radiation safety: time, shielding and distance. It also defines several terms related to radiation and x-rays such as sievert, absorbed dose, and thermionic emission. Additionally, it covers sources of radiation including radon and internal radiation, the linear attenuation coefficient, components of an x-ray machine, types of stress, and the ALARA principle of keeping radiation exposure as low as reasonably achievable.

1. 1 - Radiation safety elements : time, sheilding and distance.
2 -what are the differences bw the two x-ray types (char and brem) ?
3- Definitions: * Thermionic emission.
* Sievert.
* Absorbed dose.
* Creep.
* Atomic Emission
* Background Radiation
* Thermal Diffusivity
* Thermal Conductivity
* Ductility.
4- Sources of radiation >> the diagram ( radon , internal . bla bla bla ) + their
percentages.
5- I= Io e-μx
What is μ? >> Total linear attinuation coef.
and its unit ? >> 1/cm
What is x ? >> Thickness of material
6- X-ray machine components.
7- The ankle's diagram >> forces
8- Lever classes.
9- Types of stress (tensile , compressive and shear)
10- ALARA; As Low As Reasonably Achievable
13- Refraction, Reflection stuff; the equation (n1sinQ1=n2sinQ2)
14- Properties of laser; (Single wavelength, coherent & collimated)
15- Stress-Strain Diagram (Elastic region, elastic limit, bla bla bla)