Chapter 1- Essential concepts of radiologic science Questions with Complete Solutions

Physics - the science of matter and energy and the relationship between the two. the study of interactions of matter and energy in all their diverse forms Everything in nature can be classified as either what two things? - matter or energy Matter - is anything that occupies space. It is the material substance with mass of which physical objects are composed. Exists as: solid liquid gas atoms, molecules Mass - The quantity of matter contained in any physical object. We can consider mass and weight to be the same. measured in grams, kilograms (100 grams), etc. We usually use the concept of weight instead of mass. Energy - Measured in joules or electron volts (eV). is the ability to do work. Types of energy - - potential energy -kinetic energy -chemical energy -electrical energy -thermal energy -nuclear energy -electromagnetic energy- used in X-ray imaging potential energy - is the ability to do work by virtue of position. Kinetic energy - is the energy of motion chemical energy - is the energy released by a chemical reaction. Ex: type of energy is that which is provided to our bodies through chemical reactions involving the foods we eat. EX: battery Electrical energy - represents the work that can be done when an electron moves through an electric potential difference (voltage). Ex: all electric apparatus, such as motors, heaters, and blowers, function throughout he use of electrical energy. Thermal energy (heat) - is the energy of motion at the molecular level. It is kinetic energy of molecules and is closely related to temperature. The faster the molecules of a substance are vibrating, the more thermal energy the substance has and the higher is its temperature. Nuclear energy - is the energy that is contained within the nucleus of an atom. We control the release and use of this type of energy in electric nuclear power plants.