Class X - SSLC - Physics Quick Reference Notes

Class X - SSLC - Physics Quick Notes : 7 - Energy Management

Energy Management
Fuels:- It is Substances that release plenty of heat energy on burning.

Properties of 4 good Fuel
Easily Available.
No. Corbon monoxide Produced.
Should have high Calorific value.
Should have easily storage machanism.
No atmospheric. pollution.

Advantage of Complete Combustion
More heat energy is Produced.
Corbon monoxide is not formed
Ignition temprature is vary low

Drawbacks of partial Combustion
Carbon monoxide is produced
Loss of Fuel and Time.
Fuel does not burn completely

Coal : Main component is Carbon .Based om Carbon content it is classified into  4 Groups.
Peat, Lignite,anthracite, and Bituminous Coal. Coal is distilled absence of air Ammonia, Coal gas  Coal tar and Coke is produced.

CNG  (compressed natural gas)
The main component is methane.
Used as fuel in vehicle and thermal power station.
it Liqufied and  and transported to distant places conveniently.

LPG(Liquified Petroleum gas)
It is obtained by fractional distillation of Petroleum
It is colorless and  odourless gas.
Butane is main constituent.
Ethyl mercaptan is used to detect gas leakage.
Biological waste commonly called Biomass

Problem that arise due to combustion of biomass
Smoke is formed.
Carbon monoxide is formed.
Gasses like SO2 also formed.

Biogas : Bio waste is deposited in biogas plant in the absence of oxygen biogas is formed by the action of bacteria.
Main constituents - Methane and CO2

Advantages of biogas
Creator calorific value
No bad smell
Atmospheric pollution is minimised due to the absance of soot and smoke produced.
Slurry discharge from the biogas plant is good manure.

Hydrogen as fuel
Highest calorific value .
Abundant in nature.
No atmospheric pollution.

Hydrogen not used at domestic fuel
Possibility of explosion.
Difficult to storage.
Difficult to transport.
Hydrogen is used as fuel in rocket.

Electricity from light
Solar cell which convert light energy electricity. PN junction diode is main Part.
When light falls on N side of a solar cell , a small electric current is obtained due to the flow of electrons to P region from N region . This phenomenon is called photo voltaic effect. It is used to Space Station radio or TV relay station.

Nuclear fission
The process of nuclei of Greater mass are split into lighter nuclei using neutrons
Atom bomb.
Nuclear reactor.
Nuclear power station.

Nuclear fusion
It is the process of lighter nuclei combined to form heavier  nuclei.
Energy produced in star
Hydrogen bomb

Energy changes ->  nuclear energy ->   heat energy  -> mechanical energy  -> electrical energy

Green energy   (Clean Energy)
Green energy is the energy produced from Natural Sources that does not cause environmental pollution. Example :  Solar, wind, wave ,  energy from Biomass
Brown energy : Energy produced from Non Renewable sources such as petroleum and nuclear energy are called brown energy. Example : Atomic reactors, diesel engine, thermal power station
Reducing energy crisis as per as possible
Judicious utilization of energy
Maximum utilization of solar energy
Use public transport system
Use more efficient engine
Timely maintenance of machines

Quick Notes Recap
  1. Combustion :- Complete combustion ; Partial Combustion.
  2. Fuel :- Renewable ( solar, wind, water (hydro), biomass)  and Non renewable(coal, nuclear, oil, and natural gas).
  3. Fossil Fuels :- Petroleum, Coal (Fossil fuels sre formed from organic material over the course of millions of years)
  4. Efficiency of fuels :- Calorific value (The energy contained in a fuel or food)
  5. Biomass :- Biogas (Biogas is the mixture of gases produced by the breakdown of organic matter in the absence of oxygen (anaerobically), primarily consisting of methane and carbon dioxide)
  6. Solar Energy :- Solar Cell, Solar Panel, Solar Devices
  7. Solar Thermal Power plant :- Energy from wind, enegery from sea, Geothermal energy.
  8. Nuclear Energy :- Nuclear Fission, Nuclear Fusion.
  9. Green Energy, Brown Energy
  10. Energy Crisis, Remedies

Class X - SSLC - Physics Quick Notes : 6 - Vision and the word of colours

Near point is the nearest point at which the object s can be seen distinctly.

The near point of an eye with healthy vision is 25 cm.

Far point is the farthest point at which the object s can be seen distinctly. The far point of an eye with healthy vision is at infinity.

The ability of the eye to form an image on the retina by adjusting the focal length of the lens , irrespective of the object, is the power of accommodation. For a person with long sightedness the
size of the eye ball is smaller or power of the eye lens is low

Long sightedness can be corrected by using convex lens of suitable focal length.

For a person with short sightedness size of the eye ball is larger or the power of the eye lens is high.

Short sightedness can be rectified by using concave lens of suitable focal length.

When sunlight is passed through a glass prism spectrum VIBGYOR is obtained.

Sunlight is composite light.

Red colour is seen at the upper edge of the rainbow.

Violet colour is seen at the lower edge of the rainbow.

When an object is viewed by a person, its image remains in the retina of the eye for a time interval of 1/16 second after seeing it. This phenomenon is called Persistence of vision.

Scattering is the change in direction brought out by the irregular and partial reflection of light when it hits the particles of the medium.

As the size of the particle increases, the rate of scattering also increases.

If the size of the particle is greater than the wavelength of light, then the scattering is same for all colours.

Class X - SSLC - Physics Quick Notes : 5 - Refraction of light

The ratio of the sine of the angle of incidence to the sine of the angle refraction $$\frac{Sin i}{Sin r}$$ will always be a contact. This is known as Snell’s Law
\frac{Sin i}{Sin r} = W
n = Refractive index

The refractive index of one medium with respect to another is called Relative Refractive Index.

The refractive index of a medium with respect to vacuum is called Absolute Refractive Index.

$$Refractive index  = \frac{Speed Of Light In Air}{Speed Of Light Medium}$$
$$n  = \frac{C}{V}$$

When a ray of light passes from a medium of greater optical density to that of lower optical density, the angle of incidence at which the angle of refraction become 90° is the critical angle.

When a ray of light passes from a medium of higher optical density to a medium of lower optical density at an angle of incidence greater than the critical angle, the ray is retlected back to the same medium without undergoing refraction This phenomenon is known as total internal reflection.

A lens is a transparent medium having spherical surfaces.

Principal axis is the imaginary line that passes through the optic center joining the two centers of curvature.

A convex lens has real principal focus.

A concave lens has virtual principal focus.

Nature of image formed by convex lens depends on the position of the image

A concave lens always forms virtual image.

Magnification of real image is negative

Magnification of virtual image is positive.

$$Magnification = \frac{Height Of The Image}{Height Of The Object}$$
$$m = \frac{h_i}{h_o}$$
$$ m  = \frac{Image Distance}{Object Distance}$$
$$ m  = \frac{V}{U}$$
If magnification is possitive the image will be virtual and erect.
If the magnification is negative, the mage will be real and inverted

Power of Lens : Power of a lens in the reciprocal of focal length expressed in metre.
$$ P  = \frac{I}{f}$$
If the power is -ve , the lens is concave lens.
If the power is +ve , the lens in convex lens
The unit of power is droplet (D)

Class X - SSLC - Physics Quick Notes : 4 - Reflection of Light


  • Laws of reflectionWhen light is reflected from a smooth surface , the angle of incidence and angle of reflection are equal. The incident ray the reflected ray and the normal to the surface are in the same plane.
  • When light falls on a smooth surface, it undergoes a regular reflection.
  • When light falls on a. rough surface it undergoes an irregular reflection.
  • After regular reflection the light rays travel parallel.
  • The field of view of a mirror is the maximum range of the vision through the mirror.
  • New Cartesian Sign Convention
    In all experiments related to lens and mirrors the distances are measured in the same way as in graphs.
    Distance are measured considering the pole of the mirror as the origin.
    Those measured to the right from O are positive and those in the opposite direction are negative.
    Distance measured upwards from X axis are positive and those downwards are negative.
    The incident ray is to be considered as travelling from left to right.
  • Magnification
    The ratio of the height of the image to the height of the object is magnification.
    Magnification = 1, Size of the image = Size of the object
    Magnification > 1, Size of the image > Size of the object
    Magnification < 1. Size of the image < Size of the object
    Magnification positive - Image erect and virtual
    Magnification negative - Image inverted and real

Formulae to remember
Number of images(n)

$$n = \frac{360}{\Theta}-1$$
$$\Theta = Angle-between-mirrors$$
Focal length (f)  =
$$\frac{uv}{u + v}  $$
 $$\frac{1}{f} =  \frac{1}{u} + \frac{1}{v} $$
f = Focal length, U = Distance to object from the mirror, V = Distance to the image from the mirror.
Magnification
$$ m = \frac{hi}{ho}$$
$$ m = \frac{-v}{u}$$

hi :  Hight of image
ho : Hight of object

Class X - SSLC - Physics Quick Notes : 3 - Electromagnetic induction

In AC generator the rotating part is armature.
$$\frac{V_{s}}{V_{p}} = \frac{N_{s}}{N_{p}} ,  \frac{V_{s}}{V_{p}}  = \frac{l_{p}}{l_{s}} $$
Electromagnetic induction
Whenever there is change in the magnetic flux linked with a coil, an cmf is induced in Ihe coil. This phenomenon is electro- magnetic induction.

Fleming's right hand rule
Imagine a conductor moving perpendiculor to a magnetic field. Stretch the fore fingure, middle finger and thump of the right hand mutually perpendicular directions. If the fore finger represents the direction of the magnetic field and thump respresents the direction of motion of the conductor, then, the middle finger represents the direction of the induced current. Fleming's right-hand rule (for generators) shows the direction of induced current when a conductor attached to a circuit moves in a magnetic field. It can be used to determine the direction of current in a generator's windings.

AC Current
Current that changes direction at regular intervals of time, is an alternating currenl(AC).Alternating current (AC) is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction.

DC Current
A current that flows only in one direction contiously is a direct current. Direct current is the one directional or unidirectional flow electric charge.

Mutual induction
Consider two coils of wire kept side by side. When the strength or direction of the current in one coil changes, the magnetic flux around it changes. As a result, an cmf is induced in the secondary coil. This phcnoncnon is the mutual induction. Mutual induction is defined as the property of the coils that enables it to oppose the changes in the current in another coil.

Self induction
The change in magnetic flux due to the flow of an AC in a solenoid will generate a back cmf in the same solenoid in a direction opposite to that applied to it. This phenoenon is known as the self induction. Induction of an electromotive force in a circuit by a varying current in the same circuit.

Inductor
Inductor arc coils used to oppose the changes in electric current in a ciruit. They are used to control current in a circuit to the desired value without loss of power

Class X - SSLC - Physics Quick Notes : 2 - Magnetic effect of electric current - 2

9. Important parts of electric motor:
  • Field magnet
  • Armature coil
  • Graphite brushes
  • Split ring commutator
  • Split ring commutator helps to change the direction of current.
10. Determination of polarity of a current carrying solenoid:
  • The end of the solenoid at which current llows in the clockwise direction will be the South Pole and the end at which current flows in the anticlockwise direction will be the North Pole.
  • The end of the current carrying solenoid which repel the North pole of the magnet is the North Pole and the end of the solenoid which repel the South Pole of the magnet is the South Pole.
11. Motor Principle:
  • A current carrying conductor in a magnetic field experiences a force
  • Devices that work on the basis of motor principle:
    (i) Electric motor (ii) Moving coil loudspeaker
12. Energy conversion in motor and loud speaker:
  • Electric motor: Electrical energy to Mechanical energy
  • Moving coil loudspeaker: Electrical energy to Sound energy
13. Important parts of Moving coil loudspeaker:
  • Field magnet
  • Voice coil
  • Diaphragm.
14. Working of moving coil loudspeaker:
  • The electrical pulses from the microphone are strengthened and passed through the voice coil.
  • Thus the voice coil placed in the magnetic field moves to and fro rapidly according the electric pulses.
  • Thus the diaphragm vibrates and reproduces sound.
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Class X - SSLC - Physics Quick Notes : 2 - Magnetic effect of electric current - 1

1. Magnetic effect of electric current:
  • A magnetic field is produced around a current carry ing conductor.
  • The direction of magnetic field depends on the direction of current.
  • The direction of magnetic field around a current carrying conductor be found by James Clerk Maxwell's Right Hand Thumb rule
2. Right hand thumb rule by James Clerk Maxwell:
  • If a current carrying conductor is held in the right hand with the thumb towards the current then other fingers encircle in the direction of magnetic field.
3. Magnetic field around a circular coil carrying current:
  • If the current is in clockwise direction, magnetic field is directed into the coil.
  • If the current is in anticlockwise direction, magnetic field is directed out of the coil
4. Solenoid:
  • A solenoid is an insulated wire wound in the shape of a helix.
  • A current carrying solenoid act as a magnet
5. Differences between the magnetic fields of Solenoid and bar magnet:
  • Bar magnet:
  • Magnetism is permanent.
  • Polarity' cannot be reversed
  • Magnetic strength cannot be changed as desired
  • Solenoid:
  • Magnetism is temporary.
  • Polarity can be reversed by reversing the current
  • Magnetic strength can be increased or decreased as desired.
6. The factors affecting the magnetic effect of electricity:
  • Strength of current
  • Number of turns of the coil
7. Experiment to prove motor principle:
  • A copper rod is suspended perpendicularly between die poles of a U magnet.
  • When a current is passed, the copper rod moves in one direction.
  • When (he current is reversed, the copper rod moves in the opposite direction
  • The copper rod will move in the opposite direction if the magnetic field is reversed.
  • The direction of motion of the conductor can be found by Fleming's Left Hand Rule
8. Fleming's Left Hand Rule:
  • Hold the forefinger, middle finger and thumb of the Left I land in mutually perpendicular directions with forefinger towards the direction of magnetic field, middle finger towards the direction of current then thumb will indicate the direction of motion of the conductor.
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Class X - SSLC - Physics Quick Notes : 1 - Effects of Electric Current


  • Joule's Law : The heat generated (H) in a current carrying conductor is directly proportional to the product of the square of the current (I) in the conductor, the resistance of the conductor (R) and the time (t) of flow of current.
    H = I2Rt Joule
    Where I is the current in ampere, R is the resistance in ohm and t is the time in second.
  • When the current in the circuit is doubled, heat generated becomes four times.
  • If the current is halved, heat generated becomes  1/4 times.
  • Instruments that make use of heating effects of electric current are electric heating appliances.
  • In electric heating appliances heat is produced in heating coil.
  • Fuse wire has low melting point.
  • During overloading and short circuit the fuse wire melts and circuit breaks.
  • In incandescent lamps filaments are made up of tungsten metal.
  • Tungsten metal has high resistivity and high melting point. 
  • LED lamp gives more light but consumes less electrical energy. 
  • Effective resistance is the sum of the resistance of all the resistors 
  • Heating coils are made up of Nichrome.
  • Nichrome has high melting point and high resistivity.
  • Safety fuse is a device that works on the heating effect of electric current.
  • In order to avoid oxidation of tungsten, the bulb is evacuated, or filled some inert gas at low pressure or filled with nitrogen.
  • Color of light emitted from a discharge lamp depends on the gas filled inside the lamp.
  • Effective resistance is the sum of the resistance of all the resistors when they are connected in parallel when they are connected in series, ie,
    R = R1 + R2
  • Effective resistance is the sum of the reciprocal of all the resistors when they are connected in parallel$$\frac{1}{R}= \frac{1}{R_{1}} + \frac{1}{R_{2}} or    R=    \frac{R_{1}R_{2}}{R_{1}+{R_{2}} }$$
  • If resistors of the same value are connected in parallel, then  $$R = \frac{r}{n}$$Where n is the number of resistors and r is the resistance of one resistor.
  • The amount of energy consumed by an electrical appliance in unit time is power.
  • Units of power is watt(w)
  • Electric power (P) = I2R  $$P = \frac{V^{2}}{R} ; P = VI$$

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