Unit 1

• Motion in physics is the change in a body’s position from one location to another.
• Physics is a branch of science that studies matter and its properties, structure, motion, behavior, and interactions with other constituents.
• The main compounds and physical quantities in physics are assigned to each physical quantity the corresponding unit.
• Unit prefixes are used appropriately in physics.
• There are seven basic quantities in physics and, thus, seven basic units: length (m), time (s), temperature (K), mass (kg), electric current (A), luminous intensity (Cd), and amount of substance (mol).
• Any other quantity is derived from a combination of these basic quantities.
• Based on certain sources, there are seven disciplines in physics: mechanics, thermodynamics, electricity and magnetism, vibrations and waves, light and optics, atomic and nuclear physics, and relativity.
• Solar and wind energy, made possible by the study of physics, are an economic, sustainable, and clean alternative to fuel and gas in electricity production.
• The medical community owes the availability of many medical devices (computed tomography scanners, blood pressure tester, echography apparatus, etc.) to physicists.
• Half-life is the time needed by a radioactive mass to reduce by half and its unit is the second ( s ).
• Prefixes are used in symbol.
• Prefixes are used in nomenclature.
• Activity is the number of disintegrations of radioactive nuclei per unit time and its unit is becquerel ( Bq = s − 1 ).
• Prefixes are used in exponential notation.
• Prefixes are used for multiples and submultiples.
• Prefixes are used in unit prefixes.
• Prefixes are added to the main unit symbol to reduce the number of digits in the original value of the quantity.
• If a quantity exhibits very large or very small numbers, it is useful to reduce the number of digits by replacing some of the zeros in the number with prefix letters before the main unit symbol in SI.
• Physics involves analyzing the reasons and consequences of the behavior and interactions of material bodies, such as a bulb that illuminates when the switch is turned on, which is due to a circuit closure that allows a flow of electrons (current) generated by an electrical tension delivered by an electric source to reach the bulb.
• Physics establishes mathematical relationships (known as “laws”) between the different “quantities” that govern an observed phenomenon, such as the equation relating the voltage (U), current (I), and resistance (R) leading to a bulb illuminating (i.e., U = R · I), following the example above.
• Physics deals “experimentally” with measurements of quantities and “numerically” with calculations of those quantities.
• Nuclear power plants feeding Isar in Bavaria with electricity are an example of an application in the discipline of atomic and nuclear physics.
• To distinguish types of physical quantities, a letter or group of letter symbols is added near the value, called a “unit.”
• Luminous intensity is the amount of visible light emitted per unit time and per unit solid angle.
• Mass is the quantification of the amount of material contained in a substance.
• Thermodynamic temperature is the quantification of the level of heat stored within an object.
• Time is the quantification of a succession of events or a variable status event.
• Amount of substance is the ratio of the number of particles in a substance (atoms, molecules, etc.) to the Avogadro constant N A.
• In physics, there are only seven main quantities or “basic quantities”: length, time, thermodynamic temperature, mass, electric current, luminous intensity, and amount of substance.
• Length is a physical quantity for evaluating the location of an object measured relative to a determined reference and/or the dimensions of this object.
• General Relativity, also known as Einstein’s theory or modern physics, is a theory of gravity postulating that a gravity field is a four-dimensional space–time field that curves or warps upon the mass of the moving object.
• A “physical quantity” is an amount that can be measured and expressed by a value.
• Electric current is the rate of flow of electric charges within a circuit.
• Classical morphology and characteristics of atoms, atomic and nuclear physics examine the energetic aspect of atoms, such as interactions between their electric clouds and light photons and their nuclei, where many radiation types are also generated, such as X-rays and light.
• There are seven main disciplines in physics: Mechanics, Thermodynamics, Electromagnetism, Optics, Atomic and Nuclear Physics, and Quantum Mechanics.
• Mechanics is the branch of science that studies the motion status of bodies, consisting of two fields: statics, which deals with bodies at rest said to be in “static equilibrium,” and dynamics, which deals with bodies in either accelerated or decelerated motions.
• Thermodynamics is the branch of science that studies the effects of changes in temperature, volume, and pressure on the behavior of a substance and the influence on the interaction of this substance with its surroundings.
• Electromagnetism is the branch of science that studies the interaction of electrical and magnetic fields.
• Optics is the branch of science that studies the behavior and properties of light.
• Atomic and Nuclear Physics is the branch of science that studies the structure and behavior of atomic and nuclear systems.