Download File - Physics Made Easy

FUNDAMENTAL PRINCIPLES
OF
PHYSICS
By
Mrs. CHITRA JOSHI
PGT (PHYSICS)
KENDRIYA VIDYALAYA FRI
DEHRA DUN
CLASS VI
THE EARTH AND SOLAR SYSTEM
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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
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ATMOSPHERE- PROTECTS EARTH FORM EXCESS ENERGY AND
HARMFUL EFFECTS FROM SUN.
•
EARTH AND NINE PLANETS REVOLVE AROUND THE SUN
-
CALLED SOLAR SYSTEM.
MEASURMENTS
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SI.UNITSLENATH -
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
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MOTION OF AN OBJECT CAN BE
RECTILINEAR
ROTATIONAL
OSCILLATROY
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MOTION CAN BE UNIFORM OF NON UNIFORM
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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
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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)
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WHAT IS MACHINE - ?
•
MACHINE IS DEVICE WHICH MAKES OUR WORK EAISER
SIMPLE MACHINE
COMPLEX MACHINE
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SIMPLE MACHINE
- i- THE LEVER
ii- THE INCLINED PLANE
iii- THE SCREW
iv- THE WEDGE
v – THE WHEEL AND AXLE
vi- PULLEY
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COMPLEX MACHINE
- TWO SIMPLE MACHINES
MAKE COMPLEX MACHINES
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LEVERS ARE OF 3 TYPES – DEPEND UPON LOAD, EFFORT AND
FULCRUM
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INCLINED PLANE TO ROLL HEAVY OBJECTS
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SCREW
-
COMBINATION OF INCLINED PLANE
AND CYLINDER
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WEDGE
-
AN INCLINED PLANE THAT MOVES
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PULLEY
-
CHANGE THE DIRECTION OF APPLIED
FORCE
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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
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INDIRECT METHODS ARE USED TO MAEASURE SMALL LENGTH
(LIKE THICKNESS).
•
ACCURACY OF MEASUREMENT DEPENDS UPON THE MEASURING
DEVICE USED.
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DENSITY
-
MASS PER UNIT VOLUME SI UNIT –KG/M3
HEAT AND TEMPERATURE
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10 c.
ONE CALORIE IS HEAT REQUIRED TO RAISE TEMP. OF 1g. OF WATER BY
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ONE CALORIE
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HEAT CAPACITY
- AMOUNT OF HEAT REQUIRED TO RAISE
TEMPERATURE OF A SUBSTANCE BY 10 C
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MELTING POINT
- TEMPERATURE AT WHICH SUBSTANCE
CHANGES FROM SOLID TO LIQUID
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BOILING POINT
- TEMPERATURE AT WHICH SUBSTANCE
CHANGES FROM LIQUID TO GAS.
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HEAT TRANSFERS BY CONDUCTION, CONVECTION AND RADIATION.
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SOLID IN CONTACT WITH OTHER SOLIDS TRANSFER HEAT THROUGH
CONDUCTION.
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LIQUIDS AND GASES CONDUCT HEAT THROUGH CONVECTION.
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HEAT TRANSFER IN VACCUM IS BY RADIATION eg. SOLAR ENERGY
REACHES EARTH THROUGH RADIATION.
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METALS LIKE COPPER, SILVER, ALUMINUM AND IRON ARE GOOD
CONDUCTORS OF HEAT.
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AIR IS ALSO POOR CONDUCTOR OF HEAT.
= 4.186 JOULES.
LIGHT
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AN OBJECT WHICH HAS ITS OWN LIGHT IS CALLED A SOURCE.
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SOURCE OF LIGHT ARE NATURAL AND MAN MADE.
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LIGHT TRAVELS IN STRAIGHT LINE.
•
TRANSPARENT MATERIALS ALLOW FREE PASSAGE OF LIGHT
THROUGH THEM.
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TRANSLUCENT MATERIALS ALLOW ONLY PART OF LIGHT TO BE
PASSED THROUGH THEM..
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OPAQUE MATERIALS DO NOT ALLOW LIGHT TO PASS THROUGH
THEM.
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UMBRA
- THE DARKEST REGION OF A SHADOW.
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PENUMBRA
- WHERE LIGHT DOES NOT REACH FROM ALL
PARTS OF THE SOURCE.
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LIGHT CHANGE DIRECTION WHEN FALL ON POLISHED SURFACE
- REFCLECTION OF LIGHT.
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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.
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CURVED POLISHED SURFACES FORM SPHERICAL MIRRORS.
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SPHERICAL MIRRORS ARE OF TWO TYPES-
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CONVEX MIRROR
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CONCAVE MIRROR
IMPROTANT TERMS ABOUT SPHERICAL MIRRORS ARE PRINCIPAL AXIS,
FOCUS AND CENTER OF CURVATURE.
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CONCAVE MIRRORS FORM REAL, INVERTED IMAGES EXCEPT WHEN
OBJECT BETWEEN MIRROR AND FOCUS.
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CONVEX MIRRORS ALWAYS FROM VIRTUAL IMAGE.
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CONVEX MIRRORS ARE USED AS REARVIEW MIRRORS IN CARS. ETC.
SOUND
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SOUND IS PRODUCED BY VIBRATING OBJECTS.
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IMPORTANT TERMS ARE
AMPLITUDE, FREQUENCY, AND TIME PERIOD.
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FREQUENCY IS MEASURED IN HERTZ (Hz).
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LARGER THE AMPLITUDE OF VIBRATION LOUDER IS THE SOUND.
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HIGHER THE FREQUENY OF VIBRATION HIGHER IS THE PITCH.
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FOR HUMAN EARS AUDIBLE RANGE IS 20 Hz TO 20000 Hz.
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SOUND TRAVELS MUCH SLOWER THAN LIGHT.
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SOUND GETS REFLECTED ECHO IS PRODUCED.
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MUSICIS IS PLEASANT SOUND.
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NOISE IS UNPLEASANT SOUND.
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HUMANS PRODUCE SOUND BY VIBRATION OF VOCAL CORDS.
ELECTRIC CHARGES AT REST
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RUBBING BODIES TOGETHER CAN CHARGE THEM.
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CHARGED BODY ATTRACTS SMALL BITS OF PAPER.
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TWO TYPES OF CHARGES EXIST IN NATURE POSITVE & NEGATIVE.
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LIKE CHARGES ATTRACT UNLIKE CHARGES REPEL.
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ELECTRO SCOPE IS A SIMPLE DEVICE TO DETECT PRESCENSE OF
CHARGE ON A BODY.
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CHARGING BY CONTACT PRODUCES SAME CHARGE.
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CHARGING BY INDUCTION PRODUCES OPPOSITE CHARGE.
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LIGHTNING IS ELECTRIC DISCHARGE OF THE CHARGES OF THE
CLOUDS.
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LIGHTNING CONDUCTOR PROTECTS PROPERTY AND HUMAN LIFE
AGAINST LIGHTNING STRIKES.
CLASS VIII
UNIVERSE
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STARS ARE CELESTIAL BODIES THAT EMIT THEIR OWN LIGHT AND
HEAT.
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SUN IS ALSO A STAR.
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CONSTELLLATIONS ARE GROUP OF STARS THAT APPEAR TO FORM A
PATTERN.
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SATELLITES ARE CELESTIAL BODIES REVOLIING AROUND PLANETS.
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SOLAR SYSTEM
- SUN, 9 PLANETS, ASTEROIDS, COMET,
METEORS AND METEORITES.
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SATELLITES
- ARE NATURAL – LIKE MOON ARTIFICIAL –
USED IN COMMUNICATION, RESEARCH,
REMOTE SENSING, AND DEFENCE.
REFRACTION OF LIHGT
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SPEED OF LIGHT DIFFERENT IN DIFFERENT TRANSPARENT
MEDIUM.
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LIGHT TRAVELS WITH MAXIMUM SPEED IN VACUUM.
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WHEN LIGHT ENTERS FROM ONE TRANSPARENT MEDIUM TO
ANOTHER – IT CHANGES ITS PATH KNOWN AS REFRACTION .
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RATIO OF SPEED OF LIGHT IN TWO MEDIA
= REFRACTIVE INDEX OF ONE MEDIUM WITH RESPECT TO THE
OTHER.
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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
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FLOW OF ELECTRIC CHARGES IN A CONDUCTOR IS CALLED
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INSULATORS
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CELLS ARE SOURCE OF ELECTRIC CURRENT e.g. VOLTAIC CELL, DRY
CELL, DANIEL CELL, BUTTON CELL,
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CELLS ARE OF TWO TYPES – PRIMARY CELL AND SECONDARY CELL
CURRENT.
MATERIAL WHICH DO NOT ALLOW
ELECTRIC CURRENT.
eg. LEAD STORAGE BATTERY. THEY CAN BE RECHARGED.
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BUTTON CELLS ARE MADE UP OF SPECIAL MATERIALS.
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MAGNETS
-
SHOW SPECIAL PROPERTIES eg.
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THEY ATTRACT PIECES OF IRON
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THEY ALIGN THEM SELVES ALONG THE
NORTH SOUTH DIRECTION.
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MAGNETS HAVE TWO POLES
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LIKE POLES REPEL EACH OTHER
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UNLIKE POLES ATTRACT EACH OTHER.
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POLES CANNOT BE SEPARATED.
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EARTH BEHAVES LIKE A GIANT MEGNET.
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CURRENT CARRYING WIRE BEHAVES LIKE A MAGNET.
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CURRENT CAN BE GENERATED IN A COIL BY CHANGING MAGNETIC
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NORTH AND SOUTH.
ENERGY
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ENERGY SOURCES ARE OF TWO TYPES.
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RENEWABLE LIKE, SOLAR, WIND, WATER, BIOGAS.
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NON RENEWABLE LIKE COAL AND PETROLEUM.
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FUELS -SUBSTANCES WHICH BURN TO PRODUCE ENERGY.
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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
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PROCESS OF BURNING FUELS
-COMBUSTION.
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SOLAR ENERGY APLICATION
-SOLAR CELLS, SOLAR COOKER,
SOLAR DRYER, SOLAR WATER HEATER
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WIND ENERGY BY WIND MILLS.
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HYDROELECTRIC POWER GENETATION USES POTENTIAL ENERGY OF
WATER.
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BIOGAS
•
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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.
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BY NUCLEAR FUSION eg: SOLAR ENERGY.
CLASS IX
MEASUREMENT
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SI MEANS INTERNATIONAL SYSTEM OF UNITS
FUNDAMENTAL STRUCTURE OF SI
UNIT
SYMBOL
MASS
KILOGRAM
Kg.
LENGTH
METRE
M
TIME
SECOND
S
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
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DISPLACEMENT
-
SHORTEST DISTANCE FROM
INTIAL POSITION OF A
ITS FINAL
-
WHEN VELOCITY IS CONSTANT.
BODY TO
POSITION.
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UNIFORM MOTION
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NON UNIFORM MOTION -
WHEN VELOCITY IS NOT
CONSTANT.
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VELOCITY
DISPLACEMENT PER UNIT
TIME IN A GIVEN
-
DIRECTION
UNIT IS m/s.
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ACCELERATION
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MOTION OF A BODY CAN BE SHOW BY 3 EQUATION OF MOTION
•
-
V
= u + at
S
= ut + 1/2 at2
V2
= u2 + 2as
RATE OF CHANGE OF
VELOCITY OF A BODY.
MOTION OF A BODY IN CIRCULAR PATH ITS SPEED MAY BE
CONSTANT ITS VELOCITY IS NOT CONSTANT WHY ? ITS
DIRECTION IS CONSTANTLY CHANGING.
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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 NEWTON
2
1 NEWTON PRODUCES ACCELERATION OF 1 m /s ON A BODY OF MASS 1Kg.
THIRD LAW OF MOTION
TO 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
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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
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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.
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UNIT OF WORK IS JOULE.
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1 JOULE = 1 NEWTON x 1 METRE
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CAPABILITY TO DO WORK BY AN OBJECT IS SAID TO POSSESS ENERGY
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ENERGY AND WORK HAVE THE SAME UNIT
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BODY IN MOTION - KINETIC ENERGY
K.E. = 1/2 mv
•
2
BODY HAS ENERGY DUE TO CHANGE IN POSITION OR SHAPE POTENTIAL ENERGY
P.E. = m.g.h
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ENERGY CAN BE CHANGED FROM ONE FORM TO ANOTHER
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ENERGY CAN NEITHER BE CREATED NOR IT CAN BE DESTROYED.
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THE RATE OF DOING WORK IS POWER
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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
0
RAISE THE TEMPERATURE OF A BODY OF MASS 1 Kg BY 1 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
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PERIODIC MOTION
OSCILLATORY OR
VIBRATORY MOTION
- MOTION OF AN OBJECT WHICH REPEATS IT SELF
REGULARLY AFTER FIXED INTERVAL OF TIME
- WHEN OBJECT MOVES TO AND FRO ABOUT ITS
MEAN POSITION PERIODICALLY AND REPEATEDLY
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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
CLASS X
REFLECTION AND REFRACTION OF LIGHT
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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 MIRROR
m = 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
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NEAR POINT OR LEAST DISTANCES OF DISTINCT VISION FOR HUMAN EYE 25 cm
FOR A NORMAL EYE
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VISION DEFECTS
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MYOPIA
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HYPER METROPIA - FAR SIGHTED NESS - CORRECTED BY CONVEX LENS
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PRESBYOPIA
- CORRECTED BY BIFOCAL LENS
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ASTIGMATISM
- CYLINDERICAL LENS
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HUMAN EYE
- VISION - RETINA
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IT HAS LARGE NUMBER OF CONE SHAPED CELLS
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TO SEE COLOUR
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IT HAS LARGE NUMBER OF ROD SHAPED CELLS TO SEE INTENSITY OF
LIGHT
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MICROSCOPE IS AN OPTICAL INSTRUMENT TO SEE TINY OBJECTS.
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TELESCOPE IS AN OPTICAL INSTRUMENT TO SEE DISTANT OBJECTS.
- NEAR SIGHTEDNESS - CORRECTED BY CONCAVE LENS
HEATING AND CHEMICAL EFFECTS OF
ELECTRICITY
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ELECTRIC CURRENT IS FLOW OF ELECTRONS UNIT IS AMPERE.
DIRECTION IS TAKEN OPPOSITE TO THE DIRECTION OF FLOW OF
NEGATIVE CHARGE.
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CELL IS A DEVICE WHICH CAUSES FLOW OF ELECTRONS IN A CIRCUIT.
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RESISTANCE
- PROPERTY OF A SUBSTANCE TO OPPOSE THE FLOW OF
ELECTRONS. UNIT IS OHM.
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OHM'S LAW
- CURRENT IS DIRECTLY PROPORTIONAL TO POTENTIAL
DIFFERENCE AND INVERSELY PROPORTIONAL TO
RESISTANCE
I = V/R
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RESISTANCE OF A SUBSTANCE DEPENDS UPON
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LENGTH OF THE CONDUCTOR
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AREA OF CROSS SECTION OF THE CONDUCTOR
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MATERIAL OF THE CONDUCTOR
R=P L/A
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RESISTANCE CONNECTED IN SERIES
R = R1+ R2+ R3.....
RESISTANCES CONNECTED IN PARALLEL
1/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}
ELECTROLYTE
MANGNESE DIOXIDE
DEPOLARISER
MAGNETIC EFFECTS OF ELECTRIC CURRENT
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MAGNETIC FIELD IS A REGION IN WHICH A MAGNETIC FORCE CAN BE
DETECTED.
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FIELD LINES ARE USED TO REPRESENT A MAGNETIC FIELD.
•
WIRE CARRYING AN ELECTRIC CURRENT HAS A MAGETIC FIELD
ASSOCIATED WITH IT.
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CURRENT CARRYING CONDUCTOR PLACED IN A MAGNETIC FIELD WILL
EXPERIENCE A FORCE.
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THIS BECAME THE BASIS OF AN ELELCTRIC MOTOR WHICH CONVERTS
ELECTRICAL ENERGY TO MECHANICAL ENERGY.
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ELECTROMAGNETIC INDUCTION – WHEN MAGNETIC FIELD IS CHANGED
ACROSS A COIL CURRENT IS PRODUCED.
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GENERATORS ARE MADE ON THE PRINCIPLE OF ELECTROMAGNETIC
INDUCTION.
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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.
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.