FSc ICS Notes Physics XI SQ & Definitions Chapter 1 Measurements

FSc ICS Notes Physics XI Short Questions & Definitions Chapter 1 Measurements 1st Year Physics Notes Online Taleem Ilm Hub

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Science: The inventory of all things observable together with carefully drawn statements about the habitual behaviour of things animate and inanimate.

Physics: It is the study of the properties of matter, energy and of their mutual relationship.

Philosophy: The study and knowledge of the principles that cause, control, or explain facts and events.

Natural Philosophy: The study and knowledge of facts and events pertaining to physical universe.

Biology: The science, which deals with the origin and life history of plants and animals including botany and zoology.

Biological science: The science, which deals with living things.

Natural science: Relating to the physical universe of a particular branch of nature.

Physical: Pertaining to nature; material as opposed to moral or spiritual.

Physical science: The science, which deals with non-living things.

Chemistry: The study of the elements and compounds they form.

Astronomy: The science, which treats of the heavenly bodies, their composition, their distances, their motions, and the laws which control them.

Geology: The science that collects, studies, and explains the facts about the history of the earth and its life, especially as recorded in the rocks.

Mechanics: The study of the effects of forces on matter.

Heat & Thermodynamics: The study of heat and thermodynamics with inter-linked matters.

Heat: Heat is a form of energy associated with molecular motion.

Thermodynamics: Study of quantitative relationships between heat and other forms of energy.

Electromagnetism: The study of electricity and magnetism with inter related phenomena.

Electricity: The nature and effects of moving or stationary electric charges.

Magnetism: The study of the nature and cause of magnetic force fields, and how different substances are affected by them.

Optics: Branch of Physics which deals with the study of the behaviour of light.

Sound: The series of disturbances in matter to which the human ear is sensitive. Also similar disturbances in matter above and below the normal range of human hearing.

Hydrodynamics: A branch of science of deformable bodies, being a study of the motion of fluids. (liquid and gases)

Special relativity: It gives a unified account of the laws of mechanics and of electromagnetism. It is concerned with relative motion between non- accelerated frames of reference.

General relativity: It deals with general relative motion between accelerated frames of reference.

Quantum Mechanics: A branch of Mechanics that deals with quantum numbers and other applications of the quantum theory.

Atomic physics: Branch of physics that deals with the structure and interaction of atoms and ions with one another, and their interaction with electromagnetic field and free electrons.

Molecular physics: Branch of physics, which deals with structure and properties of molecules.

Nuclear Physics: It deals with the questions of nuclear structure and the radiation from unstable nuclei.

Solid State Physics: The study of the structure and physical properties of solids.

Particle Physics: Study of elementary particles, the fundamental constituents of all matter.

Super conductivity: The effective disappearance of electrical resistance in certain substances when  they are cooled close to absolute zero.

Super-fluid: A fluid that flows without any resistance.

Super fluidity: A property of liquid helium at very low temperatures. At 2.186 K liquid helium makes a transition to a super-fluid state, which has a high thermal conductivity and flows without friction.

Plasma: A highly ionized gas containing approximately equal numbers of positively charged ions and negatively charged electrons.

Plasma Physics: The study of the properties and behaviour of the matter in plasma state.

Magneto hydrodynamics (MHD): The study of the behaviour of a conducting fluid (e.g. an ionized gas, plasma, or collection of charged particles) under the influence of a magnetic flux.

Plasma: A mixture of free electrons and ions or atomic nuclei. Plasmas occur in thermonuclear reactions, as in the Sun.

Magnetic flux: The strength of the magnetic field through an area, based on the idea of the number of lines of force passing through the area.

Space physics: The study of the properties and behaviour of celestial bodies and regions above the earth.

Astrophysics: The study of the internal structure, properties, and evolution of celestial bodies, and the production and expenditure of energy in such systems and in the universe as a whole.

Celestial: Pertaining to the heavens; as stars are celestial bodies.

Biophysics: Physics of biological systems, with the use of physical methods in the study of biological problems, and with the biological effects of physical agents.

Chemical physics: Branch of physics which deals chemical laws based upon quantum physics.

Engineering physics: Branch of physics which deals with the design and construction of public works such as roads, railways and harbours.

Geophysics: The Physics of the Earth and the air and space surrounding it.

Medical physics: The application of physics to medicine, as in the radiotherapy, nuclear

medicine, and medical electronics.

Radiotherapy: The use of the beams of ionizing radiation, such as, X-rays, gamma rays, and energetic electrons in the treatment of cancer.

Nuclear medicine: The branch of medicine concerned with the application of radioactive nuclei in diagnosis and therapy.

Electronics: The study and use of circuitry involving such components as semiconductors, resistors, capacitors, and inductors.

Physical oceanography: Physical study and description of the ocean.

Music: The art or science of making pleasing or harmonious combinations of sound tones.

Noise: Sound produced by irregular vibrations in matter.

Harmony: A combinations of musical tones which is pleasant to the ears.

Physics of music: Physics of expressions in sound, in melody and harmony, including composition and executing, especially instrumental performance.

Telescope: An optical system for collecting radiation from a distant object and producing an enlarged image.

Radio telescope: A type of telescope used in radio astronomy to record and measure the radio frequency emissions from celestial radio sources.

Radio astronomy: The study of astronomy through the radio signals emitted by some celestial body.

Radio: Use of electromagnetic radiation to transmit or receive electrical impulses or signals without connecting wires. Also the process of receiving or transmitting such signals.

Radio waves (Hertzian waves): Electromagnetic radiation produced by rapid reverses of current in a conductor.

Expanding universe: Lines in the spectrum of the light from remote galaxies are shifted towards the long wavelength end by an amount that is greater for those galaxies known to be farthest away. This leads to the conclusion that the distance between clusters of galaxies is continuously increasing.

Big-bang theory: The theory in cosmology that all matter and radiation in the universe originated in a violent explosion that occurred 10-20 x 109 years ago. Since this initial state of extreme density & temperature, universe has expanded and cooled.

Galaxy: A giant assembly of stars, gas, and dust held together and organized largely by the gravitational interactions between its components. Galaxies contain most of the observable matter in the universe.

Proton: An elementary particle having a rest mass of 1.6725 x 10(-27) kg with a unit positive electric charge.

Neutrons: An elementary particle with zero charge and a rest mass of 1.67492 x 10(-27) kg.

Neutrons are nucleons, found in all nuclides except Hydrogen's isotope Protium.

Mesons: Elementary particles, that more massive than electrons but lighter than protons and neutrons. Mesons are thought to be involved in the exchange forces between nucleons in the nucleus.

Nucleon: A particle found in the nucleus of atoms; i.e. a proton or a neutron.

Molecule: A single atom or a group of atoms joined by chemical bonds. It is the smallest unit of a chemical compound that can have an independent existence.

Physics: It is the study of the properties of matter, energy and of their mutual relationship.

Electromagnetic radiation: Energy propagated by vibrating electric and magnetic fields.

Electromagnetic radiation forms a whole electromagnetic spectrum, depending upon frequency and ranging from high frequency cosmic rays to low frequency microwaves.

Cosmic rays: High-energy particles, apparently coming from beyond our solar system.

Microwave: An electromagnetic wave with a wavelength in the range 1 mm to 100 mm, i.e. with a frequency in the range 300 to 3GHz.

Nuclear Physics: It deals with the questions of nuclear structure and the radiation from unstable nuclei.

Nucleus (plural Nuclei): The positively charged dense central part of an atom.

Relativistic Mechanics: Mechanics based on theory of relativity which leads to four-dimensional space-time concept.

Solid State Physics: The study of the structure and physical properties of solids.

Physical chemistry: The study of physical changes associated with chemical reactions and dependence of physical properties on chemical composition.

Biophysics: Physics of biological systems, with the use of physical methods in the study of biological problems, and with the biological effects of physical agents.

Astrophysics: The study of the internal structure, properties, and evolution of celestial bodies, and the production and expenditure of energy in such systems and in the universe as a whole.

Celestial: Pertaining to the heavens; as stars are celestial bodies.

Health physics: A branch of medical physics concerned with the health and safety of personnel in medical, scientific, and industrial work. It is most particularly concerned with protection from ionizing radiation and from neutrons.

Information technology (IT): Any form of technology, primarily electronic equipment and techniques, used by people to handle and distribute information. It includes the technology of both computing and of telephony, television, and other forms of telecommunication.

Chip: A small piece of a single crystal of semiconductor material containing either a single electronic component or an integrated circuit.

Diameter: The length of a straight line through the centre of a circle.

Metalloid: One of those non-metallic elements that resemble the metals in some of their properties, as arsenic and antimony.

Semiconductor (or Semiconductor device): A material such as silicon or germanium that has a resistivity midway between that of conductors and that of insulators.

Silicon: (14Si) An element of fourth group of periodic table, having four electrons in its outermost shell called valence electrons. It is used in semi-conductor devices in the form of single crystal.

Physical quantity: The quantity, in terms of which, the laws of physics are expressed, e.g. mass, length, and time, etc.

Mass: A measure of the quantity of matter.

Length: Basic dimension for measuring linear translation.

Time: A measurable period during which something exists, continues, or takes place.

Velocity: The distance covered in unit time in a particular direction.

Force: That which produces or prevents motion, or has a tendency to do so.

Density: The ratio of the mass of a substance to its volume.

Temperature: Degree of hotness as determined by a thermometer.

Electric current: A flow of electric charge.

Base quantities: Certain physical quantities such as length, mass and time.

Derived quantities: The physical quantities defined in terms of base quantities.

Velocity: The distance covered in unit time in a particular direction.

Acceleration: i. Rate of change of velocity. ii. Change of velocity in unit time.

Force: That which produces or prevents motion, or has a tendency to do so.

Accessible: Easy to reach; open to influence.

Invariable: Constant; uniform; unchanging.

Compromise: A settlement by which each party gives up something; to combine of two systems, plans, or the like, made by sacrifice on the part of each.

System International (SI):The internationally adopted system of units used for scientific purposes. It has seven base units ( the metre, kilogram, second, kelvin, ampere, mole, and candela ) and two supplementary units ( the radian and steradian ).

FPS System: The system in which the three fundamental units are the units of length, weight and time; namely, foot, pound, and second respectively.

MKS System: The system in which the three fundamental units are the units of length, mass, and time; namely, metre, kilogram and second respectively.

CGS System: The system in which, the three fundamental units are the units of length, mass, and time; namely, centimeter, gram, and second respectively.

British Engineering System: The system in which the three fundamental units are the units of force, length, and time; namely, pound, yard, and second.

Amenable: Easy to lead; ready to accept advice.

Arithmetical manipulation: To operate skillfully and artfully with numbers and figures.

Base units: There are seven base units for various physical quantities namely: length, mass, time, temperature, electric current, luminous intensity and amount of substance.

Unit: A reference value of a quantity used to express other values of the same quantity.

Derived units: The units of physical quantities expressed in terms of fundamental units.

Fundamental units: The units, for example, length, mass, and time that form the basis of most systems of units.

Supplementary units: Certain SI units, for time being, plane angle and solid angle, which are not yet classified by the General conference of Weights and Measures.

Angle: Figure formed by lines/surfaces meeting or the space between such lines/surfaces.

Plane angle: The figure formed by lines meeting in a flat or even surface.

Solid angle: The three dimensional analogue of angle; it is subtended at a point by a surface ( rather than by a line ).

Radian: The angle subtended at the centre of a circle by an arc equal in length to its radius.

Steradian: It is the solid angle (three-dimensional angle) subtended at the center of a sphere by an area of its surface equal to the square of radius of the sphere.

Newton: The force required to accelerate one kilogram of mass at the rate of one metre per second squared.

Joule: The amount of work done, when a force of one Newton acting on a body displaces it through a distance of 1 meter along the direction of force.

Watt: It is the power of an agency which does work at the rate of 1 joule per second.

Pascal: The SI unit of pressure, equal to a pressure of one Newton per square metre.

Coulomb: The SI unit of electric charge, equal to the charge transported by an electric current of one ampere flowing for one second.

Scientific notation: A system of signs or symbols of science, used in place of language.

Symbol: A mark, character or letter representing something; as a symbol in mathematics.

Prefix: A letter or a syllable placed at the beginning of a word to modify its meaning.

Micrometer screw gauge: A measuring instrument with a fine screw for very mall and accurate measuring up to 0.01 mm.

Error: A mistake; an inaccuracy.

Uncertainty: Not sure; doubtful.

Random error: Error due to fluctuations in the measured quantity.

Systematic error: Error due to incorrect design or calibration of the measuring device.

Significant figures: In any measurement, the accurately known digits and the first doubtful digit are called significant figures.

Uranium: A hard heavy, white metallic element which possesses radioactive properties, having three isotopes 92U238, 92U235, 92U234 .

Mount Everest: The highest mountain in the world, with a height 8,850 m, rises in the Himalayas on  the frontier of Nepal and Tibet.

Round: Exact; whole; complete.

Rounded off figure: The figures of whole number up to (say) two decimal point.

Accuracy: In measurements considering the relative error. The less relative error gives more accurate result.

Precision (or absolute uncertainty): In measurements considering the magnitude of error. The less magnitude of error gives more precise measurement; it is equal to the least count of the measuring instrument.

Fractional uncertainty: The ratio of the least count of the measuring instrument with the recorded reading.

Percentage uncertainty: Obtained after multiplying fractional uncertainty with 100/100 to get % of that quantity.

Primary colours: Red, yellow, green and blue, by mixing of which any desired colour may be obtained.

Four colour scheme: Combining four printing plates of primary colours to get the natural colour of certain object.

Basic colours: Black, white and red are traditional colours for chalk or crayon drawings.

Exquisite: Highly finished and refined.

Bunsen burner: A laboratory gas burner having a vertical metal tube into which the gas is led, with a hole in the side of the base of the tube to admit air.

Aluminium (Al): A silvery-white lustrous metallic element belonging to group III of the periodic table.

Mercury (Hg): A heavy silvery liquid metallic element belonging to the zinc group.

Alcohols: Organic compounds that contain the –OH group.

Pluto: Ninth planet from the Sun and outermost known member of the solar system. (Not Considered a Planet anymore)

Cesium (Cs): White, soft, chemically reactive metallic element in group 1a of the periodic table. The atomic number is 55.

Atomic clock: The clock in which the periodic process is a molecular or atomic event associated with a particular spectral line.

Dimension: A measurement of any sort; especially length, height and width.

Dimensional analysis: A technique whose main uses are: i) to test the probable correctness of an equation between physical quantities; ii) to provide a safe method of changing the units in a physical quantity; iii) to solve partially a physical problem whose direct solution cannot be achieved by normal methods.

Homogeneity (adj. homogeneous): Uniform; of the same kind or nature; composed of similar elements.

Principle of homogeneity: The dimensions of the quantities on both sides of the equation should be same, irrespective of the form of the formula.

Anchor: A heavy iron implement for securing vessel to the ground under water or any similar thing to hold fast a movable object.

Pallet: A click or pawl used to convert or reciprocating into a rotatory motion or the reverse.

Modulus of elasticity (or Elastic Modulus): The ratio of the stress on a body to the strain produced. There are various modulii of elasticity depending on the type of stress applied.

Written By: Asad Hussain