- 1 Physics PDF Notes for Competitive Exams:
Physics PDF Notes for Competitive Exams:
Following is the Physics Important One-liner Notes for SSC CGL & RRB Railway exams. You can download this Physics PDF useful for all competitive exams of UPSC (Civil services including IAS), SSC CGL, TNPSC etc.,
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Basic Physics up to Class X level is asked in Competitive Exams such as Indian Railways –ALP and Group D exams and SSC exams. Cracku brings to you the capsule – One Liners covering exam specific topics in Physics.
IMPORTANT SCIENTISTS RELATED TO PHYSICS
|A German Theoretical Physicist who developed the theory of relativity and often referred to as one of the Fathers of Modern Physics
|English Theologian considered as one of the Fathers of Modern Physics for his groundbreaking law of Motion and Gravitation
|Italian Scientist considered as the Father of Scientific Revolution
|Danish Physicist who made tremendous contributions to the understanding of Atomic Structure and Quantum Theory
Received Nobel Prize in Physics in 1922
|German Physicist and winner of Nobel Prize in Physics in 1918 for discovering “Energy Quanta”
|German Physicist considered as one of the Pioneers of the Quantum Mechanics
|British Physicist referred to as the Father of Nuclear Physics
|American Physicist – the creator of the World’s first nuclear reactor – Chicago Pile-1, known as “Architect of the Nuclear Age”
|English Scientist whose contribution to Electromagnetism and Electrochemistry is considered crucial discoveries
|French Physicist and Nobel Laureate, considered to be the first person to discover evidence of radioactivity
|Antoine Henry Becquerel
|English Physicist awarded the Nobel Prize in Physics for the discovery of Neutron
|English Physicist and Nobel Laureate credited with the discovery of Electron
|J J Thomson
|Dutch Physicist and Nobel Laureate in 1902 for the discovery and explanation of Zeeman Effect
|American Physicist and the only Person to win Nobel Prize in Physics twice in1956 and 1972
|German Astronomer known for his laws of Planetary Motion
|Indian Physicist and Nobel Laureate in 1930 for his research in the field of Light Scattering
|C V Raman
|American Physicist who won Nobel prize in 1927 for the discovery of Crompton effect which demonstrated the particle nature of Electromagnetic radiation
|American Physicist known for the significant contribution to LASER and founder of MASER
|Charles H Townes
|Irish Physicist often credited as the first person to artificially split an atom
|Italian Inventor Pioneer in the field of radio and transmission and development of Radio Telegraph System
|Austrian Physicist whose contribution to the field of Nuclear Physics is groundbreaking, often credited with the first discovery of Nuclear Fission of an Uranium
|German chemist and pioneer in the field of radioactivity, considered as the father of Nuclear Chemistry
|German Physicist credited with the founding of X-RAYS
|Irish Physicist considered as the father of Modern Chemistry
|German Physicist and Nobel Laureate for the discovery of Diffraction of X-RAYS
|Max Von Laue
|Greek Philosopher considered as the father of Western Philosophy
|Italian Physicist credited with the Invention of Electrical Battery and discovery of Methane
|American Physicist who is credited as the “Father of the Atomic Bomb”
|J Robert Oppenheimer
|SCIENTISTS WHO DISCOVERED SOME IMPORTANT ELEMENTS
|Joseph Louis Gay
Louis Jacques Thénard
Carl Wilhelm Scheele
IMPORTANT ONE-LINERS IN PHYSICS FOR RRB, SSC AND UPSC EXAMS
PROPERTIES OF MATTER
- The fundamental Principle in Physics: Matter can neither be destroyed not created but it can be transformed from one state to another.
- The smallest Unit of an element is called Atom.
- The simplest form of matter which can retain complete physical and chemical Properties
- The force of attraction between similar kind of molecules is called Force of cohesion
- The force of attraction between different kind of molecules is called Force of adhesion
- Solids have a definite shape and size because of high Intermolecular forces as the Intermolecular space is very little.
- Liquids have only definite volume but no definite shape as the Intermolecular forces are less as the Intermolecular space is large
- Gases have no definite shape and volume as the Intermolecular forces are negligible as the Intermolecular spaces are very large
|The property of the body by virtue of which it tends to regain its Original Shape and Size when the applied force is removed
|The Property of the body that has no tendency to regain its original shape and size and remain in the deformed state after removing the applied pressure.
- Stress is defined as the restoring force per Unit Area
- The restoring force is equal in magnitude and opposite in direction to the applied force also known as deforming force
- Surface Tension is defined as the tension of the surface film of a liquid caused by the attraction of the particles in the surface layer by the bulk of the liquid, which tends to minimize surface area.
|Surface Tension Decreases
Viscosity is defined as the state of being thick, sticky, and semi-fluid in consistency, due to internal friction
UNITS AND MEASUREMENT
- Basically there are two types of Quantities in Physics
- Fundamental Quantities: Which form the basis for measurement in Physics like length, mass, time etc…
- Derived Quantities: which are derived from the base/fundamental quantities and that are expressed as the combination of base/fundamental units.
The combined system of both Fundamental and Derived Quantities is called system of units
- There are at present seven fundamental quantities internationally accepted as the International System of Units
|Name of the SI Unit
|Symbol of the SI Unit
|Amount of Substance
|Other Important Units of Measurement
|Wavelength of Light
|Dyn ( 1 Dyn = 0.00001 Newton)
There are three types on nuclear radiation:
- The speed of light in vacuum is 299,792,458 meters per second
- The medium through which light can pass easily is a transparent medium
- The medium through which light can pass partially is translucent medium
- The medium through which light cannot pass is opaque medium
|The ray of light strikes the surface of a medium before reflecting back
|The ray of light which strikes back from the medium after reflection is called reflected ray
|The ray of light which that is transmitted into the second medium and travels in a different direction than the incident ray
|Two Laws of Reflection
|Angle of Incidence is equal to the angle of reflection
Incident Ray, Reflected Ray and the Normal drawn to the point of incidence all lie in the same plane
|When all parallel incident rays reflected from a plane surface are not parallel, it is diffused reflection
Images are of two types :
- An image which can be obtained on a screen is called a real image.
- An image which cannot be obtained on a screen is called a real image.
- Mirror whose spherical surface is curved inwards is called a concave mirror
- Mirror whose spherical surface is curved outwards is called a concave mirror
- The center of curvature of a concave mirror is not a part of the mirror but lies in front of the mirror
- The center of curvature of a convex mirror is not a part of the mirror but lies behind the mirror
- Convex Lens is called a converging lens
- Concave Lens is called a divergent lens
- Total internal reflection is complete reflection of a ray of light within a medium such as water or glass from the surrounding surfaces back into the medium. The phenomenon occurs if the angle of incidence is greater than a certain limiting angle, called the critical angle.
- Phenomenon of splitting of a beam of white light into its constituent colors on passing through prism is called Dispersion of Light
- Heat is the form of energy transferred between two (or more) systems or a system and its surroundings by virtue of temperature difference.
- SI unit of Heat is Joule and SI unit of Temperature is Kelvin/ Celsius/ Fahrenheit
- Absolute zero, temperature at which a thermodynamic system has the lowest energy. It corresponds to −273.15 °C on the Celsius temperature scale and to −459.67 °F on the Fahrenheit temperature scale
- Heat flows from one object to another in three ways:
|p The process by which heat is transferred from the hotter end to the colder end of an object
p Conduction happens generally in Solids
p The materials which allow heat to pass through them easily are conductors of heat. Ex: Aluminum
p The materials which do not allow heat to pass through them easily
are poor conductors of heat and are called Insulators Ex: Wood
|p Convection is the heat transfer due to bulk movement of molecules within fluids such as gases and liquids
p Convection happens in Liquids and Gases
|p The emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles which cause ionization
|Specific Heat Capacity of the substance
|The amount of heat energy required to raise the temperature of 1gram of a substance through 1° is called
- Sound is a longitudinal wave, in which the individual particles of the medium move in a direction parallel to the direction of propagation of the disturbance. The particles do not move from one place to another but they simply oscillate back and forth about their position of rest.
- The two important properties of sound are:
|The maximum displacement or distance moved by a point on a vibrating body or wave measured from its equilibrium position.
|Frequency is the number of occurrences of a repeating event per unit of time
|Determines the loudness of the sound. Larger the amplitude – louder the sound
|Determines the pitch of the sound – higher the frequency, higher the pitch
- One Important note to make, the speed of sound in a gaseous medium is inversely proportional to the square root of the density of the gas.
- Speed of sound increases with the increase in temperature of the medium
- Minimum distance of the obstacle from source of sound for hearing distinct echo is 17.2 m at 22 degrees Celsius with speed of sound in air at 344 m/s
- Reverberation is the phenomenon of prolongation of sound due to successive reflection of sound from surrounding objects
- Audible Ranges of Sound:
|< 20 Hz ( Less than 20 Hz)
|Animals like Elephants, Whales
|20 Hz to 20000 Hz
|Audible range for Huma Beings
|> 20000 Hz ( Greater than 20000 Hz)
|Animals like Bats, Dolphins
- SONAR which stands for Sound Navigation and Ranging is a device that uses ultrasonic waves to measure the distance, direction and speed of underwater.
- If the speed of the aircraft is more than the speed of sound, then the aircraft is said to have achieved supersonic speed
WORK POWER AND ENERGY
FUNDAMENTAL LAW OF CONSERVATION OF ENERGY – ENERGY CAN NEITHER BE CREATED NOR DESTROYED, CAN ONLY BE TRANSFORMED FROM ONE FORM TO ANOTHER
- Work is done when a force that is applied to an object moves that object. Technically, Work done on an object is defined as the magnitude of the force multiplied by the distance moved by the object in the direction of the applied force.
- Unit of Work is Joule – J
- Power is defined as the rate of doing work. SI unit of Power is Watt
- Energy is the capacity of a physical system to do work. There are two types of Energy.
|The energy possessed by a body due to its change in position or shape is called the potential energy
|The energy which a body possesses by virtue of being in motion
- Pressure is defined as the force acting per unit area
- The mass per unit volume of a substance is called Density
- The relative density of a substance is the ratio of the density of the substance to the density of the water
- A form of energy resulting from the existence of charged particles (such as electrons or protons), either statically as an accumulation of charge or dynamically as a current
- Substances can be categorized into three types based on conductivity
|a conductor is an object or type of material that allows the flow of an electrical current in one or more directions
|An electrical insulator is a material whose internal electric charges do not flow freely; very little electric current will flow through it under the influence of an electric field
|A material that is neither a good conductor of electricity nor a good insulator, but has properties of electrical conductivity somewhere between the two
|Silver, Copper, Iron
- The potential difference between two conductors is equal to the work done in conducting a unit positive charges from one conductor to the other conductor through a metallic wire
- Electric Current is the rate at which electric charges pass through a conductor
- There are two main types of current in our world.
|which is a constant stream of charges in one direction
|Which is a stream of charges that reverses direction
- The obstruction offered to flow of current by the conducting wire is called its resistance
- A magnet is a piece of metal with a strong attraction to another metal object
- Magnet produces Magnetic field around itself
- Every magnet has two poles, called the north and south poles. Magnetic poles exert forces on each other in such a way that like poles repel and unlike poles attract each other
- Important Properties of Magnet
|A magnet attracts magnetic materials towards itself
|Unlike poles attract each other and like poles repel each other
|A freely suspended bar magnet always aligns in the north-south direction
|If a magnet is cut into two pieces each piece will behave like an independent magnet, with a north pole and a south pole
|A magnet with a single pole does not exist
- The phenomenon due to which an un-magnetized magnetic substance behaves like a magnet, due to the presence of some other magnet, is called magnetic induction.
- The branch of physics which deals with the relationship between electricity and magnetism is called electromagnetism.
- Whenever current is passed through a straight conductor it behaves like a magnet. The magnitude of magnetic effect increases with the increase in the strength of current.
- The action or process of moving or being moved is called motion.
- Important Terms in Mechanics:
|The rate at which someone or something is able to move or operate
This is the scalar quantity of Velocity
|The distance covered by an object in a specified direction in unit time interval is called velocity
|Acceleration, in physics, is the rate of change of velocity of an object with respect to time
|Acceleration Due to Gravity
|The acceleration which is gained by an object because of gravitational force is called its acceleration due to gravity. The acceleration due to gravity at the surface of Earth is represented as g.
|Something that causes a change in the motion of an object
|There are two types of Forces
|Centripetal Force: a force which acts on a body moving in a circular path and is directed towards the center around which the body is moving.
Centrifugal Force: a force, arising from the body’s inertia, which appears to act on a body moving in a circular path and is directed away from the center around which the body is moving.
|Mass: the quantity of matter in a body regardless of its volume or of any forces acting on it and is an independent Quantity.
SI Units of Mass : Kg
|Weight: the force exerted on a body by gravity and is dependent quantity. The value of weight changes on earth, moon, mars etc…however the mass of the body remains constant everywhere.
SI Unit of Weight : Newton
IMPORTANT INSTRUMENTS AND DEVICES IN PHYSICS
|Device used to measure energy directly in kilowatt hours
|Device used to measure energy indirectly by recording the volume of gas used
|A gauge that measures and displays the instantaneous speed of a vehicle
|An instrument used to measure the rotation speed of a shaft or disk, as in a motor or other machine
|Scale used to compute a speed based on travel time or measure distance based on speed
|one of the flight instruments in an aircraft used to inform the pilot of the rate of descent or climb
|A device used to determine the area of an arbitrary two-dimensional shape
|Is a device that used to measure proper acceleration
|a device used for measuring the speed of wind
|Is a scientific instrument used in meteorology to measure atmospheric pressure
|is a device for measuring force, torque, or power
|a measuring instrument used to measure the current in a circuit
|an electromechanical instrument used for detecting and indicating electric current
|an instrument used for measuring electrical potential difference between two points in an electric circuit
|an electrical instrument that measures electrical resistance, the opposition to an electric current
|instrument used to measure the heating power of radiation
|Similar to Actinometer designed to measure the solar radiation flux density
|remote-sensing thermometer used to measure the temperature of a surface
|an instrument used to measure the viscosity of a fluid
|an instrument used to measure the surface tension of liquids or surfaces
|an instrument that measures motion of the ground caused by activities like an earthquake, a volcanic eruption etc…
|a device for measuring the density of a material.
|a scientific instrument originally used to split light into an array of separate colors.
|an instrument used for measuring the water vapor in the atmosphere, in soil, or in confined spaces
|an apparatus for measuring the volume of air inspired and expired by the lungs
|an apparatus for measuring the amount of heat involved in a chemical reaction or other process.
|depth finder for determining depth of water or a submerged object by means of ultrasound waves
|an instrument for measuring the density of liquids.
This PDF covers One-Liners in Physics important for railway exams ALP and Group D, SSC Exams and UPSC. Crack Government Exams the smarter way with “Cracku”
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