*The branch of science concerned with the nature and properties of matter and energy Ans : Physics *Scientists known as fathers of Physics Ans : Einstein,Newton and Galileo *Father of Nuclear Physics Ans : Ernest Rutherford *Father of Indian Nuclear Programme Ans : Homi.J.Bhabha
UNITS AND MEASUREMENTS
*The chosen standard used for measuring a physical quantity is called Ans : Unit *Units are classified into Ans : Two *Two types of Units are Ans : Fundamental Units and Derived Units *The Units of fundamental quantities which can't be derived from any other quantities Ans : Fundamental Units *Fundamental units can be expressed in 3 kinds of measuring systems such as Ans : CGS, MKS and FPS * The Units which are derived from fundamental units Ans : Derived Units
FUNDAMENTAL UNITS
Measurement CGS MKS FPS Length Centimeter Meter Foot Mass Gram Kilogram Pound Time Second Second Second
*Modified form of MKS System Ans : SI (System International) *Globally approved form of unit system Ans : SI system *Physical quantities are divided into Ans : Scalar quantity & Vector quantity *Physical quantity having only magnitude, but no direction eg : Mass, Length, Time etc Ans : Scalar quantity *Physical quantity having both magnitude and direction eg: Velocity, Momentum, Force etc Ans : Vector quantity *Einstein proposed the General Theory of Relativity in Ans : 1915
MOTION
*The change in position of an object over time is called Ans : Motion *Actual length travelled by a body is called Distance Shortest distance from the initial to the final position of a body is called Ans : Displacement
MECHANICS
*The study of particles or bodies when they are at rest or in motion is dealt with Ans: Mechanics *Mechanics is divided into two Ans: Statics & Dynamics *The study of objects of rest is called Ans: Statics *The study of moving objects is called Ans: Dynamics
KINETICS AND KINEMATICS
*Kinetics and Kinematics are the subdivisions of Ans : Dynamics *Kinetics deals with relationship between the motion of bodies and forces acting on them *Kinematics is the study of the relationship between displacements, velocity, acceleration and time of a given motion, without considering the forces that cause the motion
Parameters
Formula
Unit Speed
*Speed Distance/Time m/s *Velocity Displacement/Time m/s *Acceleration Change in Velocity/Time m/s
TYPES OF MOTION
EXAMPLE
* Translator motion - Moving vehicles * Rectilinear motion - Motion of lift * Curvilinear motion - Motion of rocket * Circular motion - Spinning wheel * Oscillatory motion - Movement of swing * Periodic motion - Rotation of earth * Simple harmonic motion - Pendulum * Circular Motion - Orbits of planets
MOMENTUM
* The product of mass and velocity of a body Ans : Momentum P = mv [m=Mass, v=velocity] * It's a vector quantity * Unit - kg m/s * A Karate player in order to break a brick hits quickly because of Ans : Momentum
NEWTON'S LAWS OF MOTION
*Newton established the laws of motion in his book Ans : 'Principia Mathematica'
FIRST LAW OF MOTION
*Every body continues in its state of rest or uniform motion along a straight line unless compelled by an external unbalanced force *This law is based on Galileo's law of inertia eg : Passenger in a bus
SECOND LAW OF MOTION
*Rate of change of momentum is directly proportional to the external unbalanced force *It is used to express force *Represented by the equation F = Ma (F = Force, M = Mass, a = Acceleration)
THIRD LAW OF MOTION
*For every action there is an equal and opposite reaction eg : Propulsion of rocket, Swimming, Flying Birds etc.
INERTIA
*A property of a body which is unable to change its state by itself in the absense of external force called Ans : Inertia *The Law of inertia was discovered by Ans : Galileo *There are three types of inertia Ans : Inertia of Rest, Inertia of Motion and Inertia of Direction *Example of Inertia of motion Ans : An athlete runs some distance before taking a long jump *Example of Inertia of rest Ans : As the train starts moving, a man sitting inside leans backward *Example of Inertia of direction Ans : Rotating wheel of an automobile throw out mud tangentially outward
ROTATION AND REVOLUTION
*If a rotating body spins on its axis, its motion is called Ans : Spin motion or rotation motion eg: The earth spins on its own axis in 24 hrs *When an object travels around another object it is known as Ans: Revolution eg: The Earth revolving around the sun
PROJECTILE MOTION
*The motion of an object in a vertical plane under the influence of gravitational force is known as Ans : Projectile motion *Projectile path is known as Ans : Trajectory *A projectile reaches maximum range, when angle of projection is at Ans : 45° *The path of the projectile is always a Ans : Parabola
FORCE
*An influence that changes the state of rest in a straight line of a body is called - Force Ans : F = ma [m = mass, a = acceleration]
*Unit - Newton or Kg m/s2 *CGS unit - Dyne *One Newton = 10^5 dyne *Strongest force in the universe Ans:Nuclear force *Weakest force in the universe Ans:Gravitational Force *Force acting for a short time Ans:Impulsive force
CENTRIPETAL FORCE AND CENTRIFUGAL FORCE
CENTRIPETAL FORCE
*Force which acts on a body moving in a circular path and it is directed towards centre is called Ans:Centripetal force eg: Vehicle moving round a curved road requires this force (when speed increases, more centripetal force is required)
CENTRIFUGAL FORCE
*Force that acts on a body moving in a circular path and is directed away from the centre is called Ans:Centrifugal force eg : This force helps to separate cream from milk *Capability of rotating objects around a fixed axis is called Ans:Torque eg : Tightening of nut
FRICTIONAL FORCE
*Force that resists the movement of one surface over another is called Ans:Frictional Force *The substances which reduce the frictional force between moving surfaces Ans:Lubricants eg : Grease, Oil, Graphite etc.
APPLICATIONS OF FRICTION
*We can walk on ground *Car can stop with a sudden brake *Slow landing of a parachute through air
TYPES OF FRICTIONAL FORCES
*Static friction Ans:Force acts in a direction opposite to the direction of motion *Kinetic friction Ans:Force occurs when two objects are moving relative to each other or rub together *Rolling friction Ans:Force acts when two bodies role one another eg : Ball bearing operation
ADHESION FORCE
*Force of attraction between unlike molecules is termed as Ans:Adhesion eg : water drop sticks on glass surface
COHESION FORCE
*Force of attraction between like molecules is termed as Ans:Cohesion eg: water molecules join together
VISCOSITY
*Frictional force acting between parallel layers of a liquid is called Ans : Viscosity *Unit - Poise *With increase in temperature, viscosity Ans : Decreases *Viscosity of gas is less than viscosity of Ans : Liquid *Viscosity of an ideal fluid is Ans : Zero
MOBILE LIQUIDS
*Liquids having low viscosity are called Ans : Mobile liquids *Mobile liquids can flow easily eg : Water, Kerosene, Alcohol, Petrol etc
SUPERFLUIDS
*Fluids flow with zero viscosity is called Ans: Super fluids *It shows antigravitational property eg : Honey, Coal tar, Glycerine etc
SURFACE TENSION
*The property of a liquid by which the free surface of liquid acts like a stretched membrane Ans : Surface tension *Surface tension is caused due to Ans : Unbalanced molecular cohesive force *Surface tension is inversely proportional to temperature and Ans : Pressure *Surface tension of hot water is less than that of Ans : Cold water
APPLICATIONS AND EXAMPLES
*Insects to walk over the water surface *Spherical shape of rain drops *Detergents inverse the surface tension of water
CAPILLARITY
* It is the phenomenon of surface tension eg : rise of water level in plants : The chalk and blotting paper quickly absorb ink * It is due to adhesive force
ELASTICITY
* Ability of a body to return to its original shape is called Ans: Elasticity * Hierarchy of elasticity Ans: Steel > Rubber
PRESSURE
*The force per unit area is called Ans: Pressure Pressure = Force/Area *The SI Unit of pressure = Pascal or N/m2 *Unit of thrust Ans : Newton *CGS unit Ans : dyne /cm2 *Force acts more on objects having Ans : Low Surface area
ATMOSPHERIC PRESSURE
*Atmospheric pressure = 760mm of Mercury *Unit of Atmospheric pressure Ans : Bar 1 bar = 10^5 pascal *Pressure at sea level is taken as the Ans : Standard Atmospheric Pressure *Barometer is used to calculate Ans : Atmospheric Pressure *The liquid used in Barometer Ans : Mercury
*The mutual attractive force between two point masses m1 and m2, is inversely propotional to the square of the distance between them Ans : Newton's law of Gravitation Fa^m1m2/d2 ->F=G^m1m2/d2 g -> gravitational constant *Force of attraction between any two bodies in the universe is called Ans : Gravitation *Law of gravitation was discovered by Ans : Sir Isaac Newton *Weakest force in nature Ans : Gravitational Force *The force keeps the earth and other planetary objects in their orbits around the sun Ans : Gravitational Force *The acceleration with which the freely falling bodies are attracted towards the earth is called the Ans : Acceleration due to gravity (g) g = 9.8m/s2 (32.2 feet/s2) *Weight of freely falling body Ans : Zero
VALUE OF'G' IS
*Maximum at Polar regtons *Minimum at Equatorial regions *Zero at the center of the earth *Universal Law of Gravitation was put forward by Ans : Sir Isaac Newton *The 'g' is maximum on Jupiter and minimum on the planet Ans : Mercury *Astronaut cannot drink lemonade with the help of a straw because Ans : There is no atmosphere on the moon
ESCAPE VELOCITY
*Minimum speed which a body must have to escape from the earth's gravitational force is called Ans : Escape Velocity *Escape velocity of moon Ans : 2.4 km/s *Escape velocity of earth Ans : 11.2km/s *Escape velocity of planet Jupiter Ans : 60km/s *Escape velocity of planet Mercury Ans : 4.2km/s *Escape velocity of the planets increases with its Ans : Mass
LIGHT
* Scientific study of light Ans : Optics * Light is an Ans : Electromagnetic Wave & Transverse wave * It behaves as wave and particle. Thus light has dual nature * Light travels through air or vacuum at a speed of Ans : 3 x 108m/s *Order of speed of light Ans : water < glass < air < vacuum *Velocity of light is greater than the Ans : Sound *Light reaches earth from sun in Ans : 8 minutes 20 seconds (500seconds) *Substances which do not pass light through them are called Ans : Opaque substances eg : paper, stone *Substances which allow light to'pass through them are called Ans : Transparent substances eg : glass *Wave theory of light was proposed by Ans : Christiaan Huygens *Electromagnetic theory of light was propsed by Ans : James Clark Maxwell *'The Corpuscular theory' related to light was proposed by Ans : Isaac Newton in 1675 *The shadow obtained from a point source is a region of darkness which is called Ans : Umbra
COLOURS
*Colour of any transparent object depends on the colour of the light transmitted by it *Colour of any opaque object depends on the colour of light it reflects *Spectrum of white light - Ans : Light consits of seven colours such as Violet, indigo, Blue, Green Yellow, Orange and Red (VIBGYOR) *The band of seven colours obtained due to the dispersion of white light is called Ans : Visible Spectrum *When frequency increases wave length Ans : Decreases * Deviation most through glass prism Ans : Red * Deviation least through glass prism Ans : Violet * Colour with maximum frequency Ans : Violet * Colour with minimum wavelength Ans : Violet * Colour with maximum wavelength Ans : Red * Colour with minimum frequency Ans : Red *Colour used In laboratory for Indicating danger Ans : Yellow *Colour sensitive to human eye Ans : Yellow *Colour used as danger signal Ans : Red
DISCOVERIES
SCIENTISTS
*Corpuscular theory - Isaac Newton *Wave theory - Christiaan Huygens *Quantum Theory - Max Planck *Electromagnetic theory - James Clark Maxwell *Photo electric effect - Heinrich Hertz *A white surface reflects all form's of light and heat *A black surface absorbs all forms of light and heat *Red light passing through a green object, appears Ans : Black *Sky appears blue - Due to the shorter wavelength of blue colour, it is scattered more than the red colour of longer wavelength
PRIMARY COLOURS AND IT'S COMBINATIONS
*Primary colours are Ans : Red, Green, Blue *Primary colours used in colour television are Ans : Red, Green, Blue *Colour television uses Ans : Additive colour mixing *By mixing suitable mixture of primary colours gives Ans : Secondary colours eg : Magenta, Cyan, Yellow *Green Red = Yellow *Blue Red = Magenta *Green Blue = Cyan *Green Blue Red = White *The branch of physics which deals with the measurement of light emitted by objects is called Ans : Photometry *Tertiary colours: Ans : Mixing up of two secondary colours
COMPLEMENTARY COLOURS
: Complementary colours are the primary colours which give white colour when put together with the secondary colours *Green Magenta -->White *Blue Yellow -->White *Red Cyan -->White *The substances used in colour paints, filters, plastics and other materials Ans : Pigments *Subtractive colour mixing is used in Ans : Pigments For printing, colour pigments used are Ans : Yellow, Magenta, Cyan
QUANTUM THEORY
*The light rays consist of small energy packets called Ans : Quantum *Quantum of light is known as Ans : Photon *Quantum Theory was put forward by Ans : Max Planck *Absorption of light of one wave length by a substance and the re-emission of light of greater wavelength is called Ans : Flourescence *Emission of light in the visible region after absorbing certain electromagnetic radiations is called Ans : Photoluminescence
PHOTOELECTRIC EFFECT
*Photoelectric Effect was proposed by Ans : Heinrich Hertz *Photoelectric Effect was explained by Ans : Albert Einstein *For his explanation of Photoelectric Effect, he got Nobel prize for Physics in Ans : 1921 *Metal surfaces like Sodium, Potassium, Zinc will eject electrons when electromagnetic radiations fall upon them *The Law of Photoelectric Effect was formulated by Ans : Albert Einstein *The working principle of solar cells Ans : Photoelectric Effect
REFLECTION
*When a ray of light falls on a smooth surface and returns to the same medium, it is called Ans : Reflection of light *An object which reflects all colours appears as Ans : White *An object which absorbs all colours appears as Ans : Black
REFRACTION
*The bending of light when a ray of light travels from one medium to another is called Ans : Refraction *Snell's law is related with Ans : Refraction
EXAMPLES FOR REFRACTION
*Twinkling of stars *A pond looks shallow *Stick appears to be bended, when immersed in water *Early sunrise and late sunset *Mirage
SNELL'S LAW
*The ratio of the sine of angle of incidence in the first medium to the sine of angle of refraction in the second medium is a constant for a given pair of medium and for a given wavelength of light Ans : N - Sine i /Sine r *Due to change of medium the phase velocity of the wave is changed but its frequency remains Ans : Constant *Fatamorgana is a term associated with Ans : Mirage *The measure of optical density of the medium is Ans : Refractive index *Refractive index of a medium =Speed of light in vacuum /Speed of light in medium
*The complete reflection of a light ray reaching an interface with a less dense medium when the angle of incidence exceeds the critical angle is called Ans : Total Internal Reflection *The father of fibre optics Ans : Narendra Singh Kapani
APPLICATIONS
In the construction of *Optical fibres *Endoscopy *Vehicle reflectors *Binoculars etc
EXAMPLES
*Sparkling of diamond *Working principle of optical fibres *Glittering of water bubbles
DISPERSION
*The splitting up of light ray into different colours is called Ans : Dispersion *Dispersion was discovered by Ans : Sir Isaac Newton *Rainbow is formed due to Ans : Reflection, Refraction and Dispersion of light *Main principle due to the formation of rainbow Ans : Dispersion *Rainbow is seen as circle from Ans : Space *Rainbow is seen as semi-circle from Ans : Earth *Rainbow appears in the opposite direction of Ans : Light *Red colour angle in rainbow Ans : 42.8° *Violet colour angle in rainbow Ans : 40.8° *Colour at top of a rainbow Ans : Red *Colour at bottom of a rainbow Ans : Violet *Colour at centre of a rainbow Ans : Green
INTERFERENCE
*The phenomenon that occurs when two waves meet while travelling along the same medium Ans : Interference *Interference was observed first by Ans : Thomas Young
APPLICATIONS AND EXAMPLES
*Different colour of the soap foam *Oil spread in water *Colours that appear on the upper layer of oil that spread on road *Holography, Holograms
DIFFRACTION
*The bending of light around the corners of an obstacle or aperture into the region of geometrical shadow of the obstacle is called Ans :Diffraction
APPLICATIONS AND EXAMPLES
*The fuzzy uneven edges of shadow *Principle behind the working of projector in a film theatre *Fringes pattern in CD
SCATTERING OF LIGHT
*The reflection of a ray from a straight path due to particles or in the interface between two media is called Ans : Scattering of Light
EXAMPLES
*Reddening of sun at sunrise and sunset *The blue colour of the sky and sea *Colour lamp used in fog for veicles Ans : Yellow light *On moon, sky appears black colour due to the absence of Ans : Scattering of light *Rayleigh scattering Ans : Due to this blue colour of the sky and yellow tone of the sun *The scientist who explained the blue colour of the sky Ans : Rayleigh *The scientist who explained the blue colour of sea Ans : C.V.Raman
TYNDAL EFFECT
*Scattering of light by colloidal particle is termed as Ans : Tyndal effect
EXAMPLES
*Sunlight passing through the mist *Twinkling of comet *Blue colour seen in the smoke emitted by motor cycles
MIRRORS AND LENSES
*Spherical Mirrors are of Ans : Two types *Concave mirror Ans: Reflecting surface curved inward *Convex mirror Ans : Reflecting surface curved outward
CONCAVE MIRROR CAN BE USED
*As a shaving mirror *Reflector in solar cooker *Reflector in astronomical telescope *Search light and head light of automobiles *Used by dentists and ENT specialists *Used as burning glass *Used in torches
CONVEX MIRROR CAN BE USED AS
*Rear view mirror in automobiles *Device to check theft in shops *The mirror forms a virtual or real image depending on the position of the object Ans : Concave mirror
LENS
*A transparent medium bounded by two surfaces atleast one of which is curved surface is called Ans: Lens *The lens thicker at the middle than in edges is called Ans: Convex Lens *The lens thicker at edges than in the middle Ans: Concave lens *The unit of power of lens Ans: Dioptre *Power and focal length of convex lens Ans: Positive *The power and focal length of concave lens Ans: Negative *Lens in human eye Ans: Convex lens *Image formed in concave lens Ans: Virtual and erect
ALTERNATIVE NAMES
*Converging lens - Convex lens *Diverging fens - Concave lens *Converging mirror - Concave mirror *Diverging mirror - Convex mirror *Image formed in Convex lens Ans: Real and inverted *The shortest distance for clear vision is Ans: 25cm *Twenty - Twenty means Ans: Perfect vision
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EYE RELATED DISORDERS AND THE LENSES USED
*Myopia/Shortsightendness Can be corrected by using Ans: Concave lens * Hypermetropia / long sightedness Can be corrected by using Ans: Convex lens *Both Myopia and hypermetropia Can be corrected using Ans: bifocal lenses *Astigmatism Can be corrected by using Ans: cylindrical lens *Presbyopia Can be corrected by Ans: convex lenses
EXTRA POINTS
*Persistence of vision of human eye Ans: 1/16 seconds *Magnification Ans: height of image / height of the real object *Mirror equation = 1/u1/v=1/f
LASER
Fullform : Light Amplification by Stimulated Emission of Radiation *LASER sources have only one type of wavelength *LASER was discovered by Ans : Theodore Maiman (1960) *LASER is used in the medical field to perform minute operations [w]
MASER
Fullform : Microwave Amplification by Stimulated Emission of Radiation *MASER was discovered by Charles.H.Towns
RADAR
Fullform : Radio Detection and Ranging *Uses radiowaves to detect the position of objects such as missile, aeroplanes etc . *RADAR was invented by Ans : Albert.H.Taylorand Leo.C. Young
POLARISATION
*The phenomenon of confining the vibrations of a transverse to a particular direction is called Ans : Polarisation *Nicol prism is a Polaroid *A natural polarizing material is Ans : Tourmaline *Brewster's Law is associated with Ans : Polarisation of Light
APPLICATIONS
*Used in windows of aeroplanes and cars *Sunglasses *3 dimensional motion pictures
DOPPLER EFFECT
*A change in frequency of light wave when the source or the observer moves with respect to one another is called Ans : Doppler effect *High pitch of the siren of an approaching ambulance which passes an observer is due to Ans: Doppler effect *Two types of shift occur due to this phenomenon (1) Red Shift Ans : Decrease in frequency of the visible light when it moves away from the observer (2) Blue shift : Increase in frequency of the visible light when it moves towards the observer
ELECTROMAGNETIC RADIATION
*The pattern of arrangement of different types of electromagnetic radiations in the order of increasing wavelength Ans : Electromagnetic spectrum *Arrangement of radiations in the increasing order of wave length Ans : Radiowaves > Microwaves > IR-rays > Visible light > UV rays > X - rays > Gama rays > Cosmic rays *Maximum wavelength of electromagnetic wave Ans : Radio waves *Waves used for communication through satellite Ans : Microwaves
X-RAYS
*Electromagnetic waves with shorter wavelength Ans : X-rays *Two types of X-rays (1)Soft X-rays: Having high wavelength and low energy used in radiations (2)Hard X-rays: Having short wavelength and high energy *X-rays were Discovered by Ans: Roentgen *Rays used to study the internal atomic structure of crystal Ans : X-rays *Rays appear to be originated from outside of earth is called Ans : Cosmic rays *Cosmic rays was discovered by Ans : Victor Hess
INFRARED RAYS (IR RAYS)
*Infrared Rays was discovered by Ans : William Herschel *Heat rays emitted by sun is Ans : Infrared rays
USES AND EXAMPLES
*Infrared rays is used in TV remote *Infrared rays is used in distant photography *Heat of sun is due to Ans : Infrared rays
ULTRAVIOLET RAYS (UV RAYS)
*The electromagnetic radiation with wavelength ranging from 10nm to 380nm Ans : Ultraviolet Rays
APPLICATIONS
*For identifying the counterfeit currency *Used to fill inside the tube lights *Used to disinfect equipment used for operation *It causes sunburn
WAVES
*The disturbance which propagates energy from one place to another without the transport of matter Ans : Waves
TWO TYPES OF WAVES
*Longitudinal wave *Transverse wave *Particles vibrate parallel to the direction of propagation of wave Ans : Longitudinal wave eg : sound wave *Particles vibrate perpendicular to the direction of propagation of wave Ans : Transverse wave eg : Light wave *The distance between two successive crests or troughs Ans : Wave length *The maximum displacement of vibrating particle on either side from the equilibrium position Ans: Amplitude *The spatial frequency of a wave, either in cycles per unit distance or radians per unit distance is called Ans: Wave Number *Earthquake waves are Ans: Infrasonic waves
SOUND
*A form of energy which produces sensation of hearing Ans: Sound * Sound requires a Ans: Medium to travel * Sound cannot travel through Ans: Vacuum * Study of sound is called Ans: Acoustics * Velocity of sound in air Ans: 340m/s * Velocity of sound is maximum in Ans: Solids * Velocity of sound is least in Ans: Gases * Sound has the maximum speed in Ans: Steel * The number of oscillation made in one second is called Ans: Frequency Unit of frequency - Hertz (Hz) 1 cycle/second -1 Hz * Frequency of audible sound is Ans: 20Hz to 20,000 Hz * The machine used to reproduce sound Ans: Phonogram * The method of locating under water objects using sound waves Ans: SONAR (Sound Navigation and Ranging) * Waves used in SONAR Ans: Ultrasonic waves * The phenomena of sound which is used in stethoscope Ans: Reflection of sound * The unit which is usually used to denote the intensity of pollution Ans: Parts per million (ppm) * Normal sound level in decibel Ans: 60-120 db
FACTORS OF SOUND
(1)Pitch (2)Loudness (3)Timbre / Quality
PITCH
*The shrillness of sound felt by the ear Ans: Pitch
LOUDNESS
* The intensity of sound is measured in » The intensity of sound felt by the ear Ans: Loudness
TIMBRE
*It is the quality of sound *Different individuals have different Timbre * Used to denote the speed of a supersonic plane Ans : Mach Number * 1 Mach number is equal to Ans : 340 m/s * Persistance of sound Ans : 1/10 seconds * Velocity of sound in moist air is greater than in dry air * Ultrasound scanning uses high frequency Ans : Ultrasonic waves
ECHO
*Echo and reverberation are due to the reflection of Ans : Sound *Minimum distance required for the production of echo Ans : 17m *Phenomenon utilized by bats to detect prey and obstacles in their path in night Ans : Echolocation *For echolocation bats use Ans : Ultrasonic sound *Depth of the sea is measured in Ans : Fathom 1 fathom = 6 feet = 1.82 m
HEAT
*It is an indication of object's internal energy or it is the degree of hotness/ coldness Ans : Temperature *Heat is measured in the unit of Ans : Joule (J) *The study of materials and phenomena at low temperature Ans : Cryogenics
TEMPERATURE SCALES
*Celsius scale (C) *Fahrenheit scale (F) *Kelvin or absolute scale (K) *Relationship of temperature scale C/5 = F-32/9 = K-273/5 *In Kelvin scale there is no Ans: Negative temperature *The amount of heat required to raise the temperature of the substance through it Ans : Heat capacity *Calorie was the unit, formerly used to measure Ans: Heat One calorie = 4.2 Joules *The amount of heat required to raise the temperature of lgm of water by 1°C Ans : One calorie *The instrument used for measuring high temperature Ans : Pyrometer *Amount of heat required to raise the temperature of unit mass of a substance by 1°C is Known as Ans : Specific heat capacity *Water has the highest specific heat capacity *Specific heat of water Ans : 4185 J/KgK *Specific heat of water is minimum at Ans : 37°c *Element with the highest specific heat Ans : Hydrogen *The temperature above which a gas cannot be liquefied Ans : Critical temperature *Absolute Zero Ans : = 0 Kelvin = -273.15°C *The temperature which shows same measurement in Celsius and in Fahrenheit Scale Ans : -40 *Temperature which shows same measurement in Fahrenheit and in Kelvin Scale Ans : 574.25
TRANSMISSION OF HEAT
*There are 3 modes of heat transfer 1. Conduction 2. Convection 3. Radiation
CONDUCTION
*Process of exchange of hotter particles to the neighbouring colder particles is known as Ans : Conduction *In solids, heat transfer takes place by Ans : Conduction
CONVECTION
*Transfer of heat from hotter region carrying heat to a colder region is called Ans : Convection *In liquid and gas, heat transfer takes place by Ans : Convection *Land breeze and sea breeze is due to Ans : Convection *Ocean currents Monsoon and trade winds are based on the principle of Ans : Convection
RADIATION
*Transmission of heat from one point to another without heating the medium is called Ans : Radiation *Heat from the sun reaches the earth by Ans : Radiation *Polished surface reduces radiation, results in Ans : Heat loss
THERMOMETERS
*Thermometer was invented by Ans : Galelio
TYPES OF THERMOMETERS
(1)MERCURY THERMOMETER *Invented by - Farenheit (2)CLINICAL THERMOMETER *Invented by - Thomas Allbutt *Normal temperature of human body Ans : 36.9°C ( 98.4°F, 310 K)
THERMO FLASK (VACUUM FLASK)
*Invented by Ans: Sir James Dewar *It prevents heat loss by Ans: Conduction and convection *Glass used in thermo flask Ans: Borosilicate glass
CONDUCTORS AND INSULATORS
*Substances which easily allows electricity to flow through them is called Ans : Conductors eg: silver, copper, mercury etc *Substances which does not allow electricity to pass through it is called Ans : Insulators eg: plastic, mica, rubber, dry air etc *Substances which allow electricity to flow through them partially Ans : Semiconductors eg: Germanium, Silicon *Mica is a good conductor of heat but bad conductor of Ans : Electricity *Copper and Aluminium are the metals commonly used in Ans : Electric circuit *Insulators used in electrical system Ans : Porcelain or Glass
ANOMALOUS EXPANSION OF WATER
*Almost every liquid expands with increase in Ans : Temperature *When the temperature of water is increased from 0°C to 4°C the volume Ans : Decreases *If the temperature is increased above 4°c the volume starts Ans : Increasing *Temperature at which water has least volume and high density Ans : 4°C *Water expands on Ans : Freezing *Water pipes break in winter in cold regions due to Ans : Freezing
THERMAL EXPANSION
*Tendency of matter to change in volume in response to change in temperature is called Ans : Thermal Expansion *All substances expand on Ans : Heating *Mercury thermometer works on the principle of Ans : Thermal Expansion *Matter which expand most on heating Ans : Gases
APPLICATIONS
*Rail Road tracks are constructed so that they can safely expand on a hot day without derailing the trains travelling over them. *Electri
THERMAL CONDUCTIVITY
*Property of a material to conduct heat is called Ans : Thermal conductivity *Unit (SI) of thermal conductivity Ans : Watts per meter Kelvin (W/mK) *Co-efficient of thermal conductivity Ans : K Factor *The rate of cooling of hot water will be fester than the Ans : Tap water *In a refrigerator, cooling is produced by the evaporation of a Ans : Volatile liquid
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