FUNDAMENTAL PRINCIPLES OF

PHYSICSBy

Mrs. CHITRA JOSHIPGT (PHYSICS)

KENDRIYA VIDYALAYA FRIDEHRA DUN

CLASS VI

THE EARTH AND SOLAR SYSTEM• EARTH IS SPHERICAL IN SHAPE AND IT ROTATES ABOUT AN

IMAGINARY AXIS.

• EARTH REVOLVES AROUND THE SUN IN A DEFINITE ORBIT.

• THE INTERIOR OF THE EARTH HAS THREE LAYERS.

- CRUST - UPPERMOST

- MANTLE - MIDDLE

- CORE - INNIER MOST

• ATMOSPHERE- PROTECTS EARTH FORM EXCESS ENERGY AND HARMFUL EFFECTS FROM SUN.

• EARTH AND NINE PLANETS REVOLVE AROUND THE SUN

- CALLED SOLAR SYSTEM.

MEASURMENTS• SI.UNITS-

LENATH - METRE

MASS - KILOGRAM

TIME - SECOND

TEMPERATURE - KELVIN

• NATIONAL PHYSICAL LABORATORY MAINTAINS

THE NATIONAL STANDARDS FOR ALL THE BASIC UNITS.

VOLUME-SPACE OCCUPIED BY ANY MATTER OR AN OBJECT

–SI.UNIT - CUBIC METRE (M3)

MASS -MESAURE OF THE QUANTITY OF MATTER

TIME -MEASURED BY USING EVENTS THAT OCCUR REGULARLY AND AT EQUAL INTERVALS

TEMPERATURE - DEGREE OF HOTNESS OF AN OBJECT MEASURED BY USING THERMOMETER. UNITS DEGREE

CELSIUS OR DEGREE KELVIN.

FORCE AND MOTION• MOTION OF AN OBJECT CAN BE

RECTILINEAR

ROTATIONAL

OSCILLATROY

• MOTION CAN BE UNIFORM OF NON UNIFORM

• MOTION CAN BE PERIODIC OR NON PERIODIC

• SPEED = DISTANCE MOVED IN UNIT TIME

• UNIT = METRE PER SECOND

• FORCE IS PUSH OR PULL ON AN OBJECT

WHAT FORCE CAN DO ?

IT CAN CHANGE THE SPPED OF AN OBJECT

IT CAN CHANGE THE DIRECTION OF MOTION OF AN

OBJECT

FORCE CAN CHANGE THE SIZE AND SHAPE OF THE

OBJECTS

UNIT -NEWTON

WHAT IS EARTH’S FORCE -10 NEWTON/ KILOGRAM

TYPES OF FORCE

MUSCULAR

FRICTIONAL

GRAVITATIONAL

MAGNETIC

ELECTRICAL

PRESSURE - FORCE PER UNIT AREA

FLUIDS EXERT PRESSURE

UNIT OF PRESSURE - PASCAL

ATMOSPHERIC PRESSURE IS ONE HUNDRED KILO PASCALS

FLUID PRESSURE IS MEASURED BY MANOMETER

WORK AND ENERGY

• WHAT IS WORK- ?

• WHEN FORCE IS APPLIED ON A BODY AND IT MOVES THROUGH A DISTANCE - WORK IS SAID TO BE DONE

UNIT OF WORK IS JOULE (J)

• WHAT IS MACHINE - ?

• MACHINE IS DEVICE WHICH MAKES OUR WORK EAISER

SIMPLE MACHINE

COMPLEX MACHINE

• SIMPLE MACHINE - i- THE LEVER

ii- THE INCLINED PLANE

iii- THE SCREW

iv- THE WEDGE

v – THE WHEEL AND AXLE

vi- PULLEY

• COMPLEX MACHINE - TWO SIMPLE MACHINES

MAKE COMPLEX MACHINES

• LEVERS ARE OF 3 TYPES – DEPEND UPON LOAD, EFFORT AND FULCRUM

• INCLINED PLANE TO ROLL HEAVY OBJECTS

• SCREW - COMBINATION OF INCLINED PLANE AND CYLINDER

• WEDGE - AN INCLINED PLANE THAT MOVES

• PULLEY - CHANGE THE DIRECTION OF APPLIED FORCE

• ENERGY - TWO TYPES

(i) POTENTIAL ENERGY-WORK DONE IN

RASING AN OBJECT

(ii) KINETIC ENERGY - BODY IN MOTION HAS KINETIC ENERGY

ENERGY - LIGHT, SOUND, HEAT, ELECTRCAL, MECHENICAL, CHEMICAL.

CLASS VII

MEASURMENTS• INDIRECT METHODS ARE USED TO MAEASURE SMALL LENGTH (LIKE THICKNESS).

• ACCURACY OF MEASUREMENT DEPENDS UPON THE MEASURING DEVICE USED.

• DENSITY - MASS PER UNIT VOLUME SI UNIT –KG/M3

HEAT AND TEMPERATURE• ONE CALORIE IS HEAT REQUIRED TO RAISE TEMP. OF 1g. OF WATER

BY 10 c.

• ONE CALORIE = 4.186 JOULES.

• HEAT CAPACITY - AMOUNT OF HEAT REQUIRED TO RAISE TEMPERATURE OF A SUBSTANCE BY 10 C

• MELTING POINT - TEMPERATURE AT WHICH SUBSTANCE CHANGES FROM SOLID TO LIQUID

• BOILING POINT - TEMPERATURE AT WHICH SUBSTANCE CHANGES FROM LIQUID TO GAS.

• HEAT TRANSFERS BY CONDUCTION, CONVECTION AND RADIATION.

• SOLID IN CONTACT WITH OTHER SOLIDS TRANSFER HEAT THROUGH CONDUCTION.

• LIQUIDS AND GASES CONDUCT HEAT THROUGH CONVECTION.

• HEAT TRANSFER IN VACCUM IS BY RADIATION eg. SOLAR ENERGY REACHES EARTH THROUGH RADIATION.

• METALS LIKE COPPER, SILVER, ALUMINUM AND IRON ARE GOOD CONDUCTORS OF HEAT.

• AIR IS ALSO POOR CONDUCTOR OF HEAT.

LIGHT• AN OBJECT WHICH HAS ITS OWN LIGHT IS CALLED A SOURCE.

• SOURCE OF LIGHT ARE NATURAL AND MAN MADE.

• LIGHT TRAVELS IN STRAIGHT LINE.

• TRANSPARENT MATERIALS ALLOW FREE PASSAGE OF LIGHT THROUGH THEM.

• TRANSLUCENT MATERIALS ALLOW ONLY PART OF LIGHT TO BE PASSED THROUGH THEM..

• OPAQUE MATERIALS DO NOT ALLOW LIGHT TO PASS THROUGH THEM.

• UMBRA - THE DARKEST REGION OF A SHADOW.

• PENUMBRA - WHERE LIGHT DOES NOT REACH FROM ALL PARTS OF THE SOURCE.

• LIGHT CHANGE DIRECTION WHEN FALL ON POLISHED SURFACE- REFCLECTION OF LIGHT.

• LAW OF REFLECTION - FIRST LAW IS THAT

- INCIDENT RAY, REFLECTED RAY AND POINT OF INCIDENCE ARE IN THE SAME PLANE

- SECOND LAW IS THAT

- ANGLE OF INCIDENCE IS EQUAL TO ANGLE OF REFLECTION.

• CURVED POLISHED SURFACES FORM SPHERICAL MIRRORS.

• SPHERICAL MIRRORS ARE OF TWO TYPES-

- CONVEX MIRROR

- CONCAVE MIRROR

• IMPROTANT TERMS ABOUT SPHERICAL MIRRORS ARE PRINCIPAL AXIS,

FOCUS AND CENTER OF CURVATURE.

• CONCAVE MIRRORS FORM REAL, INVERTED IMAGES EXCEPT WHEN OBJECT BETWEEN MIRROR AND FOCUS.

• CONVEX MIRRORS ALWAYS FROM VIRTUAL IMAGE.

• CONVEX MIRRORS ARE USED AS REARVIEW MIRRORS IN CARS. ETC.

SOUND• SOUND IS PRODUCED BY VIBRATING OBJECTS.

• IMPORTANT TERMS ARE

AMPLITUDE, FREQUENCY, AND TIME PERIOD.

• FREQUENCY IS MEASURED IN HERTZ (Hz).

• LARGER THE AMPLITUDE OF VIBRATION LOUDER IS THE SOUND.

• HIGHER THE FREQUENY OF VIBRATION HIGHER IS THE PITCH.

• FOR HUMAN EARS AUDIBLE RANGE IS 20 Hz TO 20000 Hz.

• SOUND TRAVELS MUCH SLOWER THAN LIGHT.

• SOUND GETS REFLECTED ECHO IS PRODUCED.

• MUSICIS IS PLEASANT SOUND.

• NOISE IS UNPLEASANT SOUND.

• HUMANS PRODUCE SOUND BY VIBRATION OF VOCAL CORDS.

ELECTRIC CHARGES AT REST• RUBBING BODIES TOGETHER CAN CHARGE THEM.

• CHARGED BODY ATTRACTS SMALL BITS OF PAPER.

• TWO TYPES OF CHARGES EXIST IN NATURE POSITVE & NEGATIVE.

• LIKE CHARGES ATTRACT UNLIKE CHARGES REPEL.

• ELECTRO SCOPE IS A SIMPLE DEVICE TO DETECT PRESCENSE OF CHARGE ON A BODY.

• CHARGING BY CONTACT PRODUCES SAME CHARGE.

• CHARGING BY INDUCTION PRODUCES OPPOSITE CHARGE.

• LIGHTNING IS ELECTRIC DISCHARGE OF THE CHARGES OF THE CLOUDS.

• LIGHTNING CONDUCTOR PROTECTS PROPERTY AND HUMAN LIFE AGAINST LIGHTNING STRIKES.

CLASS VIII

UNIVERSE• STARS ARE CELESTIAL BODIES THAT EMIT THEIR OWN LIGHT AND

HEAT.

• SUN IS ALSO A STAR.

• CONSTELLLATIONS ARE GROUP OF STARS THAT APPEAR TO FORM A PATTERN.

• SATELLITES ARE CELESTIAL BODIES REVOLIING AROUND PLANETS.

• SOLAR SYSTEM - SUN, 9 PLANETS, ASTEROIDS, COMET, METEORS AND METEORITES.

• SATELLITES - ARE NATURAL – LIKE MOON ARTIFICIAL – USED IN COMMUNICATION, RESEARCH, REMOTE SENSING, AND DEFENCE.

REFRACTION OF LIHGT• SPEED OF LIGHT DIFFERENT IN DIFFERENT TRANSPARENT MEDIUM.• LIGHT TRAVELS WITH MAXIMUM SPEED IN VACUUM.• WHEN LIGHT ENTERS FROM ONE TRANSPARENT MEDIUM TO

ANOTHER – IT CHANGES ITS PATH KNOWN AS REFRACTION .• RATIO OF SPEED OF LIGHT IN TWO MEDIA

= REFRACTIVE INDEX OF ONE MEDIUM WITH RESPECT TO THE OTHER.

• REFRACTION OF LIGHT THROUGH PRISM SPLITS IN TO SEVEN COLOURS-(VIBGYOR)

- VIOLET - INDIGO- BLUE- GREEN- YELLOW- ORANGE- RED

LENSES - CONVERGING LENSES - CONVEX LENSES- DIVERGING LENSES - CONCAVE LENSES

COVEX LENSES - OUR EYES, TELE SCOPE, MICROSCOPE.

ELECTRICITY AND MAGNETISM• FLOW OF ELECTRIC CHARGES IN A CONDUCTOR IS CALLED CURRENT.

• INSULATORS - MATERIAL WHICH DO NOT ALLOW ELECTRIC CURRENT.

• CELLS ARE SOURCE OF ELECTRIC CURRENT e.g. VOLTAIC CELL, DRY CELL, DANIEL CELL, BUTTON CELL,

• CELLS ARE OF TWO TYPES – PRIMARY CELL AND SECONDARY CELL

eg. LEAD STORAGE BATTERY. THEY CAN BE RECHARGED.

• BUTTON CELLS ARE MADE UP OF SPECIAL MATERIALS.

• MAGNETS - SHOW SPECIAL PROPERTIES eg.

- THEY ATTRACT PIECES OF IRON

- THEY ALIGN THEM SELVES ALONG THE NORTH SOUTH DIRECTION.

• MAGNETS HAVE TWO POLES - NORTH AND SOUTH.

• LIKE POLES REPEL EACH OTHER

• UNLIKE POLES ATTRACT EACH OTHER.

• POLES CANNOT BE SEPARATED.

• EARTH BEHAVES LIKE A GIANT MEGNET.

• CURRENT CARRYING WIRE BEHAVES LIKE A MAGNET.

• CURRENT CAN BE GENERATED IN A COIL BY CHANGING MAGNETIC FIELD THROUGH IT- ELECTRO MAGNETIC INDUCTION.

• ELECTRIC GENERATORS WORK ON THIS PRINCIPLE OF ELECTROMAGNETIC INDUCTION.

ENERGY• ENERGY SOURCES ARE OF TWO TYPES.

- RENEWABLE LIKE, SOLAR, WIND, WATER, BIOGAS.

- NON RENEWABLE LIKE COAL AND PETROLEUM.

• FUELS -SUBSTANCES WHICH BURN TO PRODUCE ENERGY.

• THEY CAN BE SOLID, LIQUID OR GAS.

-SOLID FUELS -eg; WOOD, AGRICULTURAL WASTES, COWDUNG CAKES,

COAL , AND CHAR COAL.

-LIQUIDS FULES -eg; KEROSENE, PETROL AND DIESEL.

-GASEOUS FUELS- BIOGAS, PETROLEUM GAS, NATURAL GAS

eg: LPG AND CNG

• PROCESS OF BURNING FUELS -COMBUSTION.

• SOLAR ENERGY APLICATION -SOLAR CELLS, SOLAR COOKER,

SOLAR DRYER, SOLAR WATER HEATER

• WIND ENERGY BY WIND MILLS.

• HYDROELECTRIC POWER GENETATION USES POTENTIAL ENERGY OF WATER.

• BIOGAS - MIXTURE OF METHANE AND CARBONDIOXIDE PRODUCED BY DECOMPOSITION OF BIOLOGICAL WASTE IN ABSCENCE OF AIR

- DEVICE IS KNOW AS BIOGAS PLANT.

• NUCLEAR ENERGY TWO TYPES

- BY NUCLEAR FISSION eg: NUCLEAR REACTOR, ATOM BOMB.

- BY NUCLEAR FUSION eg: SOLAR ENERGY.

CLASS IX

MEASUREMENT• SI MEANS INTERNATIONAL SYSTEM OF UNITS

• FUNDAMENTAL STRUCTURE OF SI

UNIT SYMBOL

MASS - KILOGRAM Kg.

LENGTH - METRE M

TIME - SECONDS

ELECTRIC

CURRENT - AMPERE A

TEMPERARURE - KELVIN K

LUMINOUS

INTENSITY - CANDELA Cd

AMOUNT OF

SUBSTANCE - MOLE Mol.

• ALL UNIT ARE DERIVED FROM THESE SEVEN BASIC UNITS.

• NPL MAINTAINS NATIONAL STANDARD OF MEASUREMENT.

• STANDARD OF IONIZING RADIATIONS ARE MAINTAINED BY BHABHA ATOMIC RESEARCH CENTER, MUMBAI.

MOTION• DISPLACEMENT - SHORTEST DISTANCE FROM

INTIAL POSITION OF A BODY TO ITS FINAL POSITION.

• UNIFORM MOTION - WHEN VELOCITY IS CONSTANT.

• NON UNIFORM MOTION - WHEN VELOCITY IS NOT CONSTANT.

• VELOCITY - DISPLACEMENT PER UNIT TIME IN A GIVEN

DIRECTION

UNIT IS m/s.

• ACCELERATION - RATE OF CHANGE OF VELOCITY OF A BODY.

• MOTION OF A BODY CAN BE SHOW BY 3 EQUATION OF MOTION

V = u + at

S = ut + 1/2 at2

V2 = u2 + 2as

• MOTION OF A BODY IN CIRCULAR PATH ITS SPEED MAY BE CONSTANT ITS VELOCITY IS NOT CONSTANT WHY ? ITS

DIRECTION IS CONSTANTLY CHANGING.

FORCE NEWTONS LAWS OF MOTION

FIRST LAW OR THE LAW OF INERTIA- - A BODY CONTINUES TO BE IN A STATE OF REST OR UNIFORM MOTION

ALONG A STRAIGHT LINE UNLESS ACTED UPON BY AN UNBALANCED FORCE.

- INERTIA - TENDENCY OF A BODY TO RESIST CHANGE. MASS IS A MEASURE OF ITS INERTIA

SEDCOND LAW- ACCELERATION PRODUCED IN A BODY IS DIRECTLY PROPORTIONAL TO

THE FORCE ACTING ON IT. MOMENTUM- OF A BODY IS THE PRODUCT OF ITS MASS AND VELOCITY AND HAS THE

SAME DIRECTION AS THAT OF VELOCITY. - ITS RATE OF CHANGE IS DIRECTLY PROPORTIONAL TO FORCE.- IN ISOLATED SYSTEM TOTAL MOMENTUM REMAINS CONSTANT.

-UNIT OF FORCE IS NEWTON1 NEWTON PRODUCES ACCELERATION OF 1 m /s2 ON A BODY OF MASS 1Kg.

THIRD LAW OF MOTIONTO EVERY ACTION THERE IS AN EQUAL AND OPPOSITE REACTION AND THEY ACT ON TWO DIFFERENT BODIES.

FRICTION - FORCE OPPOSING MOTION SLIDING FRICTION > ROLLING FRICTION

PRESSURE - THRUST PER UNIT AREA UNIT IS PASCAL

ARCHIMEDE'S PRINCIPLE

WHEN A BODY IS FULLY OR PARTIALLY IMMERSED IN A FLUID IT EXPERIENCES AN

UPWARD FORCE WHICH IS EQUAL TO THE WEIGHT OF THE FLUID DISPLACED BY IT. GRAVITATION

•LAW OF GRAVITATION - FORCE OF ATTRACTION BETWEEN TWO BODIES IS PROPORTIONAL TO THE PRODUCT OF THEIR MASSES AND INVERSELY PROPORTIONAL TO THE SQUARE OF THE DISTANCE BETWEEN THEM.

•FORCE OF GRAVITATION DUE TO EARTH IS CALLED GRAVITY.•FORCE OF GRAVITY ON A BODY CAN BE THOUGHT OF AS ACTING AT A POINT IN

THE BODY CALLED ITS CENTRE OF GRAVITY.•GRAVITATION IS A WEAK FORCE•THE FORCE OF GRAVITY DECREASES WITH ALTITUDE•THE FORCE OF GRAVITY VARIES ON THE SURFACE OF THE EARTH :IT DECREASES

FROM POLES TO THE EQUATOR. •WHEN A BODY IS PROJECTED AT AN ANGLE TO THE HORIZONTAL IS CALLED A

PROJECTILE. •THE WEIGHT OF A BODY IS THE FORCE WITH WHICH THE EARTH ATTRACTS

IT.•WEIGHT IS EQUAL TO THE PRODUCT OF MASS AND ACCELERATION DUE TO

GRAVITY.•THE WEIGHT OF A BODY CAN BE ASSUMED TO ACT AT ITS CENTRE OF

GRAVITY.WEIGHT VARIES FROM PLACE TO PLACE BUT MASS STAYS CONSTANT.

WORK ENERGY AND POWER•WORK DONE ON A BODY IS DEFINED AS THE MAGNITUDE OF THE FORCE

MULTIPLIED BY THE DISTANCE MOVED BY THE BODY IN THE DIRECTION OF THE APPLIED FORCE.

•UNIT OF WORK IS JOULE.

•1 JOULE = 1 NEWTON x 1 METRE

•CAPABILITY TO DO WORK BY AN OBJECT IS SAID TO POSSESS ENERGY

•ENERGY AND WORK HAVE THE SAME UNIT

•BODY IN MOTION - KINETIC ENERGY

K.E. = 1/2 mv2

•BODY HAS ENERGY DUE TO CHANGE IN POSITION OR SHAPE POTENTIAL ENERGY

P.E. = m.g.h

•ENERGY CAN BE CHANGED FROM ONE FORM TO ANOTHER

•ENERGY CAN NEITHER BE CREATED NOR IT CAN BE DESTROYED.

•THE RATE OF DOING WORK IS POWER

•SI UNIT OF POWER = WATT

•1 WATT = 1 JOULE/ 1SECOND

HEAT• TEMPERATURE IS THE MEASURE OF THE DEGREE OF HOTNESS (OR

COOLNESS) OF A BODY UNITS - CELSIUS, KELVIN, FAHRENHEIT• TEMPERATURE OF A BODY IS MEASURED BY A DEVICE CALLED

THERMOMETER.• HEAT IS ENERGY OF MOLECULAR MOTION.• SPECIFIC HEAT CAPACITY OF A SUBSTANCE - AMOUNT OF HEAT REQUIRED

TO RAISE THE TEMPERATURE OF A BODY OF MASS 1 Kg BY 10 c.• COEFFICIENT OF LINEAR EXPANSION - INCREASE IN VOLUME PER UNIT

VOLUME PER UNIT RISE IN TEMPERATURE. • LATENT HEAT OF MELTING - QUANTITY OF HEAT REQUIRED TO

COMPLETELY CHANGE 1 Kg. OF A SOLID TO A LIQUID STATE AT ITS MELTING POINT WITHOUT ANY CHANGE IN TEMPERATURE.

• LATENT HEAT OF VAPORIZATION - THE QUANTITY OF HEAT REQUIRED TO CONVERT 1 Kg. OF A LIQUID TO VAPOUR STATE AT THE SAME TEMPERATURE.

• BOILING POINT - IS THE TEMPERATURE AT WHICH THE VAPOUR PRESSURE IS EQUAL TO THE ATMOSPHERIC PRESSURE AT THE LIQUID SURFACE.

• EVAPORATION CAUSES COOLING• RELATIVE HUMIDITY - AT GIVEN TEMPERATURE, 1m3 OF AIR HOLD m Kg. OF

WATER VAPOUR WHEREAS IT COULD HOLD ms KG ON SATURATION THE QUANTITY.

m/ms x 100 IS CALLED RELATIVE HUMIDITY.

WAVE MOTION AND SOUND • PERIODIC MOTION - MOTION OF AN OBJECT WHICH REPEATS IT SELF

REGULARLY AFTER FIXED INTERVAL OF TIME

OSCILLATORY OR VIBRATORY MOTION - WHEN OBJECT MOVES TO AND FRO ABOUT ITS

MEAN POSITION PERIODICALLY AND REPEATEDLY • SIMPLE PENDULUM - SMALL HEAVY BODY SUSPENDED FROM ONE

END OF LIGHT LONG THREAD.• TIME PERIOD - TIME TAKEN BY THE BOB TO COMPLETE ONE

OSCILLATION.T = 2 l/g l = length of the pendulum

• FREQUENCY - NUMBER OF OSCILLATIONS PER SECOND• WAVE - DISTURBANCE OF THE MEDIUM WITHOUT

PHYSICAL TRANSFER OF MATTER. • WAVE - TWO TYPES

- LONGITUDINAL AND TRANSVERSE• AMPLITUDE - MAXIMUM MAGNITUDE OF DISPLACEMENT• WAVE VELOCITY - VELOCITY WITH WHICH A WAVE PROPOGATES• TIME PERIOD - TIME REQUIRED TO COMPLETE ONE CYCLE BY

THE WAVE.• FREQUENCY - NUMBER OF WAVES PER SECOND.• PERIODIC MOTION - MOTION OF AN OBJECT WHICH REPEATS ITSELF

REGULARLY AFTER FIXED INTERVAL OF TIME V =

SOUND WAVES PRODUCE ECHO• SONAR - SYSTEM OF SOUND NAVIGATION AND RANGING• IT USES ULTRASONIC WAVES AND REFLECTION OF SOUND

CLASS XREFLECTION AND REFRACTION OF LIGHT

• LIGHT IS A FORM OF RADIANT ENERGY • LIGHT WAVES ARE ELECTRO MAGNETIC WAVES. • SPEED OF LIGHT IS 3 x 108 M/S• MIRROR FORMULA 1/v + 1/u = 1/f• WHERE v = image distance

u = object distance f = focal length

• LINEAR MANIFICATION OF SPHERICAL MIRRORm = v/u

• FOR VIRTUAL IMAGE MAGNIFICATION POSITIVE• FOR REAL IMAGE MAGNIFICATION NEGATIVE • LENS FORMULA = 1/v - 1/u = 1/f• POWER OF A LENS IS RECIPROCAL OF ITS FOCAL LENGTH EXPRESSED IN

METRES. • UNIT OF POWER OF A LENS IS DIOPTRE.• TOTAL INTERNAL REFLECTION WHEN RAY OF LIGHT GOES FROM DENSER.TO

A RARER MEDIUM SUCH THAT ANGLE OF INCIDENCE EXCEEDS CRITICAL ANGLE

• SPLITTING OF WHITE LIGHT INTO COLOUR IS CALLED DISPERSION • PRIMARY COLOURS - RED, BLUE, GREEN• SUBTRACTIVE COLOURS - MAGENTA, YELLOWS, CYAN

OPTICAL INSTRUMENTS • ACCOMODATION OF EYE - ITS ABILITY TO FOCUS AT BOTH NEARBY AND

FAR OFF OBJECTS

• NEAR POINT OR LEAST DISTANCES OF DISTINCT VISION FOR HUMAN EYE - 25 cm FOR A NORMAL EYE

• VISION DEFECTS

• MYOPIA - NEAR SIGHTEDNESS - CORRECTED BY CONCAVE LENS

• HYPER METROPIA - FAR SIGHTED NESS - CORRECTED BY CONVEX LENS

• PRESBYOPIA - CORRECTED BY BIFOCAL LENS

• ASTIGMATISM - CYLINDERICAL LENS

• HUMAN EYE - VISION - RETINA

• IT HAS LARGE NUMBER OF CONE SHAPED CELLS

• TO SEE COLOUR

• IT HAS LARGE NUMBER OF ROD SHAPED CELLS TO SEE INTENSITY OF LIGHT

• MICROSCOPE IS AN OPTICAL INSTRUMENT TO SEE TINY OBJECTS.

• TELESCOPE IS AN OPTICAL INSTRUMENT TO SEE DISTANT OBJECTS.

HEATING AND CHEMICAL EFFECTS OF ELECTRICITY

• ELECTRIC CURRENT IS FLOW OF ELECTRONS UNIT IS AMPERE. DIRECTION IS TAKEN OPPOSITE TO THE DIRECTION OF FLOW OF NEGATIVE CHARGE.

• CELL IS A DEVICE WHICH CAUSES FLOW OF ELECTRONS IN A CIRCUIT.

• RESISTANCE - PROPERTY OF A SUBSTANCE TO OPPOSE THE FLOW OF ELECTRONS. UNIT IS OHM.

• OHM'S LAW - CURRENT IS DIRECTLY PROPORTIONAL TO POTENTIAL DIFFERENCE AND INVERSELY PROPORTIONAL TO RESISTANCE

I = V/R

• RESISTANCE OF A SUBSTANCE DEPENDS UPON

• LENGTH OF THE CONDUCTOR

• AREA OF CROSS SECTION OF THE CONDUCTOR

• MATERIAL OF THE CONDUCTOR

R=P L/A

• RESISTANCE CONNECTED IN SERIES R = R1+ R2+ R3.....

• RESISTANCES CONNECTED IN PARALLEL1/R = 1/R1 +1/R2 +1/R3....

• ELECTRIC POWER (WATT) = VOLT x AMPERE• ELECTROLYTES ARE SALTS WHOSE SOLUTIONS ARE GOOD CONDUCTORS OF

ELECTRICITY • ELECTROLYSIS IS A PROCESS OF DECOMPOSING AN ELECTROLYTE BY PASSING

ELECTRIC CURRENT THROUGH IT. • ELECTRO PLATING - PROCESS OF DEPOSITING A METAL OVER OTHER BY ELECTROLYSIS.• FARADAYS LAWS OF ELECTROLYSIS

m Q• FORA GIVEN AMOUNT OF CHARGE PASSED MASSES OF DIFFERENT ELEMENTS

DEPOSITED ON THE CATHODE ARE PROPORTIONAL TO RATIOS OF ATOMIC MASS DIVIDED BY VALENCY.

• DRY CELL - ZINC - NEGATIVE ELECTRODE CARBON - POSITIVE ELECTRODE

• AMMONIUM CHLORIDE , ZINC CHLORIDE} ELECTROLYTEMANGNESE DIOXIDE - DEPOLARISER

MAGNETIC EFFECTS OF ELECTRIC CURRENT• MAGNETIC FIELD IS A REGION IN WHICH A MAGNETIC FORCE CAN BE DETECTED.

• FIELD LINES ARE USED TO REPRESENT A MAGNETIC FIELD.

• WIRE CARRYING AN ELECTRIC CURRENT HAS A MAGETIC FIELD ASSOCIATED WITH IT.

• CURRENT CARRYING CONDUCTOR PLACED IN A MAGNETIC FIELD WILL EXPERIENCE A FORCE.

• THIS BECAME THE BASIS OF AN ELELCTRIC MOTOR WHICH CONVERTS ELECTRICAL ENERGY TO MECHANICAL ENERGY.

• ELECTROMAGNETIC INDUCTION – WHEN MAGNETIC FIELD IS CHANGED ACROSS A COIL CURRENT IS PRODUCED.

• GENERATORS ARE MADE ON THE PRINCIPLE OF ELECTROMAGNETIC INDUCTION.

• TRANSFORMERS ARE USED TO RAISE OR LOWER VOLTAGE FOR TRANS MISSION OF POWER OVER LONG DISTANCES.

• AC ELECTRIC POWER IN HOMES, VOLTAGE IS 220 V FREQUENCY IS 50 HZ, WIRE WITH RED INSULATION IS LIVE WIRE, WIRE WITH BLACK

INSULATION IS NEUTRAL WIRE, WIRE WITH GREEN INSULATION IS EARTH WIRE.

• FUSE- SAFETY DEVICE TO PROTECT CIRCUITS.

SOURCES OF ENERGY

• SOLAR CELL CONVERT SOLAR ENERGY DIRECTLY TO ELECTRICITY.

• WIND ENERGY IS USED TO DO MECHANICAL WORK OR TO PRODUCE ELECTRICITY.

• ENERGY OF FLOWING WATER, WAVES OF OCEAN AND TIDES IS USED TO PRODUCE ELECTRICITY BY BUILDING DAMS.

• ENERGY FROM BENEATH THE EARTH’S HEAT IS GEOTHERMAL ENERGY.

• GREEN PLANTS CONVERT SOLAR ENERGY TO CHEMICAL ENERGY BY PHOTOSYNTHESIS – IT IS CALLED BIO ENERGY.

• FOSSIL FUELS LIKE COAL, PETROLEUM AND NATURAL GAS ARE NON RENEWABLE ENERGY SOURCES.

• FUELS ARE CHARACTERIZED BY THEIR CLAORIFIC VALUE AND IGNITION TEMPERATURE AND BY THE NATURE OF PRODUCTS FORMED BY THEIR COMBUSTION.

• THREE CONDITIONS ESSENTIAL FOR COMBUSTION ARE ATTAINMENT OF IGNITION TEMPERATURE, PRESENCE OF OXYGEN AND A COMBUSTIBLE. MATERIAL.

NUCLEAR FISSION AND FUSION

• HIGH ENERGY PROJECTILES LIKE ALPHA PARTICLES, PROTONS AND GAMMA RAYS CAN PRODUCE A VARIETY OF NUCLEAR REACTIONS.

•. NEUTRONS ARE HIGHLY EFFECTIVE IN CAUSING NUCLEAR REACTIONS.

• LARGE AMOUNT OF ENERGY IS RELEASED IN NUCLEAR FISSION.

• LARGE AMOUNT OF ENERGY IS ALSO RELEASED IN NUCLEAR FUSION.

• WHEN TWO LIGHT NUCLEI MERGE INTO EACH OTHER TO FORM A NEW HEAVIER NUCLEUS - FUSION OCCURS.

• CONTROLLED NUCLEAR FISSION – NUCLEAR REACTOR.

• UNCONTROLLED NUCLEAR FISSION - ATOM BOMB.

• NUCLEAR FUSION - SOURCE OF ENERGY IN SUN AND STARS.

• INDIA TESTED NUCLEAR DEVICES IN MAY 1974 AND MAY 1998.