D.C Motor and A.C Generator

                                            D.C Motor
An electrical device used to convert electrical energy inta mechanical energy.

Working Principle :-
Torque is produced in a current carrying coil placed in a magnetic field.

Construction: -
→Power radial magnet.
→Rectangular coil of many turns.
→Spindal.
→Copper split rings.
→Carbon brushes.
→Battery.

Carbon brushes: -
It takes the  current from battery and deliver it to coil.

Split rings:-
Are used to change the current in the faces of coil after each haif cycle. so, to rotate the coil in same direction. (means to produce torque in the same direction) .

D.C motor diagram  elaborates it well,it is given given below.

                                                                              
                              ←→
                                   A.C Generator

An device which converts mechanical energy into electrical energy.

Working Principle :-
Farady's law of magnetic induction.

Construction: -
→Power radial magnet.
→Spindal.
→Rectangular coil of many turns.
→Copper slip rings.
→Carbon brushes.
→Galvanometer.

Working: -
Its working can be studied using e.m.f vs time figure of A.C generator.

The Diagram of A.C generator is given  which will make this topic easy to understand.

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Vitamins Sources,Uses and Diseases due to their Deficiency

Vitamins:-
Vitamins are specific organic compounds which are required by our bodies to prevent specific diseases but cannot be produced by our bodies.
There are different types of vitamins given below.

⊙Vitamin (A):-
▷Sources:-
Milk, butter  ,fish oil ,eggs, fresh green vegetables .
▷Necessary for:-
Eyes  and skin
▷Deficiency symptoms: -
Night blindness, dry skin
                                                                   ←→
⊙Vitamin (B) (a group of several vitamins) :-
▷Sources:-
Whole meal bread, rice ,yeast liver, soybeans, fresh green vegetables.
▷Necessary for :-
Energy production in cells, nerves ,skin.
▷Deficiency symptoms: -
Skin diseases, tongue inflammation, anemia ,bleeding gums.
                                                                   ←→
⊙Vitamin (C) :-
▷Sources:-
Oranges ,lemons, tomatoes, fresh green vegetables.
▷Necessary for:-
Blood vessels ,gums, healing wounds, preventing colds.
▷Deficiency Symptoms: -
Scurvy
                                                                    ←→
Vitamin (D):-
▷Sources: -
Milk, butter ,eggs ,fish oils.
▷Necessary for:-
Bones ,teeth .
▷Deficiency symptoms: -
Rickets, osteomalacia.
                                                                   ←→
⊙Vitamin (E):-
▷Sources: -
Whole meal bread ,rice ,eggs, butter, fresh green vegetables.
▷Necessary for:-
Antioxidant.
▷Deficiency symptoms: -
Hemolysis of red blood cells, sterility.
                                                                    ←→
⊙Vitamin (K):-
▷Sources: -
Fresh green vegetables, liver.
▷Necessary for:-
Clotting of blood.
▷Deficiency symptoms: -
Hemorrhage delayed blood clotting.

                                                                    ←→

Urea

UREA:-
As the world population has increased the demand for food has increased. The world population was 3.5 billions in 1965'.By 2025,it will reach 10 billions. Many people are hungry. Crop take nutrients from the soil,and these must be replaced before the next crop is sown.Fertilizers are the compounds which are put in soil to provide elements essential for plants life.They are added to the soil to make up the deficiency caused by the previous crops.Fertilizers are classified into two categories:
⊙1)Natural Fertilizers:-
Those fertilizers obtain from plants and animal wastes.
⊙2)Synthetic Fertilizers:-
Those fertilizers which are produced in industry e.g urea,ammonium sulphate,  ammonium phosphate, super phosphate and di- ammonium phosphate. Urea is one of the widely used fertilizer because of the following qualities:
☞1)Percentage of nitrogen is highest among all the synthetic nitrogen fertilizers i.e. 46 °/.  .
☞2)It does not affect the texture of the soil.
☞3)In the soil it hydrolysis quickly to ammonium carbamate which eventually changes into NH3 which decomposes into N2 and H2.Nitrogen is the main constituent of proteins;it is required by the stems and leaves during the early stages of the plant development. It imparts green colour to the leaves and
increases the yield and quality of the Crop.
⊙Raw Materials: -
The raw Materials for the manufacture of  urea are:
Manufacturing of urea consists of following steps.
▷1)Ammonia (NH3)
▷2)Carbon dioxide (CO2)
☞1)Reaction between NH3 and CO2 to form ammonium carbamate.
        2NH3  +  CO2  → NH2COONH4

☞2)Distillation of ammonium carbonate.
  
      NH2COONH4   →  NH2-C-NH2+H2O
            UREA                          ♩♩
                                                O
☞3)Evaporation of liquid urea and its granulation.
The urea solution is concentrated in vacuum evaporator, which is then rapidly cooled and sent to the prilling tower. Urea small particles thus produced are packed and then marketed.

■The flow sheet diagram for urea is made by me which will help you understand the manufacturing process easily.

Concepts of Acids and Bases

⊙Arrhenius Concept of Acids and Bases:-
In 1887,The Swedish chemist svante Arrhenius proposed the first successful theory of acids and bases
⊙Acid: -
An acid is a substance that ionizes in water to produce H+ ions.
▷Example: -
HCl,HNO3
⊙Base:-
An base is a substance that ionizes in water to produce OH- ions .
▷Example: -
NaOH,KOH
                                                            ←→
⊙The bronsted -lowery concept of Acids and Bases :-
In 1923,The J.N bronsted and T.M Lowery proposed the acid and base theory to remove defects in Arrhenius theory.
⊙Acid:-
An acid is a proton donor .
▷Example: -
H2SO4,CH3COOH,H2S
⊙Base:-
An base is a proton acceptor.
▷Example: -
H20,NH3
                                                            ←→
⊙Lewis Concept of Acid and Bases:-
In 1923, G.N Lewis proposed an acid base theory that is more general than either the Arrhenius or Bronsted- lowery theory.
⊙Acid:-
A Lewis acid is a substance that can accept a pair of electron to form a coordinate covalent bond
▷ Example: -
AlCl3,H+
⊙Base:-
A Lewis base is a substance that can donate a pair of electrons to form a cordinate covalent bond.
▷Example: -
OH-,Cl-

                                                            ←→

Important Laws

☞⊙Lens Law:-
"The direction of an induced current is always such that it opposes the cause that produce it".

☞⊙Faradys Law:-
"The induced e.m.f produce in a closed circuit is directly proportional to the time rate of change of flux. "
☞€ proportional  △Q/△t

☞⊙Joules Law:-
"Amount of heat energy generated in resistance due to flow of electric current is equal to the product of square of current I,the resistance R and time duration t."
☞W=I^2Rt

☞⊙Fleming left hand rule:-
"Fleming stretch the thumb,forefinger and middle finger of the left hand which were perpendicular to each other and if forefinger shows direction of magnetic field and middle finger shows direction of current then thumb indicates the direction of force acting on the conductor."

⊙Snells Law:-
When ray of light enters from ane particular medium  to other then ratio of sine of angle of incidence to the sine of angle of refraction is constant.
☞⊙Mathematicaly:-

    n= sine i /sine r

⊙Ohm's Law:-

"The current passing through any crossection of a conductor is directly proportion to the applied potential difference provided,the physical state of the conductet is not changed."

☞⊙Mathematicaly:-

V proportional to I

V=IR

Where 'R' is the constant of proportionality and is called ,the resistance of the conductor.

⊙Weber fechner law:-

"The loudness of sound is indirectly proportional to the log10 of intensity of sound."
☞⊙Mathematicaly:-
If 'I' is the intensity of sound then the loudness of sound is
L proportional log10 I
L=K log 10 I

⊙Law of Conservation of Momentem:-

The momentem of an isolated system of two ormorethantwo interacting bodies rmains constant.

☞⊙Mathematicaly:-

  MV + mv =0

Or

  MV = - mv

Hence

  V= - m/M × v

⊙Law of Gravitation:-

Everybody in the universe attracts every other body with a force which is directly propottional to the product of their masses and inversely proportional to the square of the distance between their centres.

☞⊙Mathematicaly:-

   F=G ( m1m2 / d^2 )

⊙Pascals Law :-

Pressure applied at any point af a liquid enclosed in  a container, is transmitted without loss to all other parts of the liquid.

⊙Archimedes Principle:-

When an object is totally or partially immersed 

In a liquid, an upthrust acts on it equal to the weight of the liquid it displaces.

⊙Principle of floatation:-

A floating object displaces a fluid having weight equal to the weight of the object.

⊙Hooke's Law:-

The strain produced in a body by the stress applied to it ,is directly proportional to the stress within the elastic limit of the body .

☞⊙Mathematicaly:-

  Stress proportional strain

  

  Stress = constant × strain

  Stress/strain = Constant

Solvay Process

                        Solvay Process 
Sodium carbonate or soda ash is an important industrial chemical.It is used in the manufacturning of glass, soaps,detergents, paper and many other important chemicals. Sodium carbonate is manufactured in a continuous process known as the Solvay process.
◎Raw Materials :-
commercially, sodium carbonate is manufactured in a continuous process that uses :
1) Ammonia
2) Brine (concentrated sodium chloride solution)
3) Lime stone as a source of carbon dioxide and slaked lime,Ca(OH)2
4) H2O(water)
◎Basic Steps :-
Solvay process consists of following steps
☞1) Preparation of ammonical brine:
Ammonical brine is prepared by dissolving ammonia gas in brineAmmonicalbrine is fed into the carbonating tower.
☞2)Carbonation:-
In the carbonating tower, carbon dioxide is passed through Ammonicalbrine.
Following reaction take place in it
CO2+NH3+H2O →NH4CO3
NH4HCO3+NaCl 15℃→  NaHCO3+NH4Cl      In the lower compartment of carbonating tower,the temperature of the mixture is lowered to 15℃. At this temperature, NaHCO3 precipitates out.
☞3)Filtration: -
Precipitates of NaHCO4 are separated from the milky solution by filtration. It is used as baking soda.
☞4)Calcinations:-
Sodium hydrogen carbonate is heated to get sodium carbonate.
2NaHCO3 heat→ Na2CO3+CO2+H20
Carbon dioxide released is re-cycled in the process.
☞5)Preparation of Carbon dioxide and slaked lime:-
Carbon dioxide is produced by heating limestone in a kiln.
CaCO3    heat → CaO+CO2
Carbondioxide is fed into the carbonating tower from the top.Equal mounts of lime(CaO) and water are mixed to produce slaked lime, Ca(OH)2
 
       CaO + H2O → Ca (OH)2
Slaked lime is pumped to the ammonia recovery tower.
☞6)Recovery of ammonia: -
Solution containing ammonium chloride produced in the carbonation tower is heated with slaked lime.
2NH4Cl + Ca(OH)2  heat → 2NH3+CaCl+2H2O
Almost all the ammonia is recovered in this process.It is reused in the process.
◎Advantages of Solvay Process: -
★It is a cheap process. The raw materials arr cheap and easily available.
★It is a pollution free process. No harmful products are produced.
★It consumes less fuel .This is because there is no solution to be evaporated.
★Carbon dioxide and ammonia are recovered and re-used in the process.
★It produces pure NaHCO3 and Na2CO3.
 

☞Flow sheet diagram of solvay process is made by me that will help you understand this process easily.

Ozone Depletion and Its Effect

                                               Ozone
      Ozone is a light blue gas and has an unpleasant odour. In the troposphere, ozone causes breathing difficulties,asthma and eye irritation. Ozone is an allotropic form of oxygen comprising of three oxygen atoms,O3 ozone is an important gas in the stratosphere.
Explanation:-
      Most of UV radiation coming from sun are filtered or scrrened out by the ozone layer .Otherwise, sunlight wouid be much more hazardous for human beings, animals and plants.On absorbing UV radiation, ozone molecule breaks up to form a oxygen molecule and atomic oxygen.
         O3 → O2 + O
Atomic  oxygen  is very reactive. Atomic oxgen reacts readily with an oxygen molecule to form ozone, there by releasing  heat
    O2 + O →O3 + heat
The destruction anf reformation of ozone are powered by UV radiation.
Human activities disturb this natural balance and  stability  of ozone  layer.
scientists have discovered a reduction in the amount of ozone  in the stratosphere .
The region in which the amount of ozone has been reduced is called as ozone hole.
ozone hole was first discovered in October, 1980 over Antarctica.

GLOBAL WARMING

Definetion :-                                                    

The warming of the atmosphere whichvis due to our influence on the greenhouse effect is known as global warming.
Explanation :-
The increasing use of fossil fuels and the deforestation have led to an increase in the levels of CO2 in the air.Gases like water vspour,methane and CFCs also act in a similar way in the atmosphere. These gases are called green house gases.
The higher the concentration of green house gases in the air,the greater is the green house effect, and greater will be the increase in temperature.
Certain human activities are threatening to cause a significant increase in the greenhouse effect.
Global warming is due to an upset in the natural balance of the concentration of greenhouse gases in the atmosphere.
If global warming continues,then
●Temperature of the earth will gradually increase.
●Polar ice may melt and cause significant increase in sea levels.
●So the atmosphere becomes hotter.
●The earth climate may change,affecting both where there is rainfall and how much there is of it.This could cause both increased risk of flooding in some regions and drought in others.

Transformer

DEFINITION: -
                       A devise used to increase or decrease the A.C voltage.
PRINCIPLE :-
                      The device works on the principle of mutual induction.
CONSTRUCTION: -
                                 It consist if a soft iron core upon which  are waunded two separate layers of coils.
The coil into which current is sent is called primary coil and other secondary coil.on picture (1)
WORKING: -
                    When the A.C current, passes through the primary coil,the changing magnetic fueld lines also passes through the secondary coil and according to farady's law e.m.f is induced in the secondary coil.
If Np and Ns are the Number of turns in primary and secondary coil respectively, and Vp and Vs are the voltage across primary and secondary coil respectively, then the transformer equation is (on picture 2 )
   
      Vp/Vs = Np/Ns  or   Vs/Vp = Ns/ Np
If Vs >Vp ; then the transformer is called step up transformers.
If Vs < Vp ; then the transformer is called  step down transformer.

House Safety Alarm

Now you can catch the burglar:-
We can use single NAND gate to make burglar alarm. This can be done by using NAND gate (combination of NOT and AND gate ),an LDR (light depending resistor), a push button Switch S and an alarm on picture attached.
Cinnect LDR between NAND gate input B and rhe positive terminal of the battery.
The LDR will cause a High level input '1' at B when in light because of its Low resistance. The LDR will cause a low level input '0' at B when light is interrupted and cause high resistance in LDR .
A low level signal is also caused at A when burglar steps on switch S.
si this burglar alarm sound when either burglar interrupts light falling on LDR or steps on switch  S.

CATHODE RAYS OSCILLOSCOPE (C.R.O)

Definition : -
                                   A device used to measure and compare time period, magnitude and amplitude.
Construction: -
(1) Electron gun:- To produce beam of electron
(2) Grid :- To control brightness               

(3) Deflecting System: - To make beam straight by (x,y) plates
(4) Screen :-A flourosent screen made of phosphorus
       
                        

LAW OF MASS ACTION

                     
INTRODUCTION :-
                                  Two chemist C.M GULDBERG and P.WAAGE in 1864 proposed the law of mass action to describe the equilibrium state.

DEFINITION  :-
                            It states that the rate at which a substance react is directly proportional to its active mass, and the rate at which the reaction proceed is directly proportional to its active masses of the reactants.

DERIVATION :-
                                  Consider a hypothetical reaction in which (a) moles of reactant A and (b) moles of reactant B react to give (c) moles of product C and (d) moles of product D at equilibrium.
                                             aA+bB     ←→ cC+dD                                                                                                                                                
MATHEMATICAL PROOF :-                                                                                                           Acording to law of mass action :-
 Rate of forward reaction proportional to [A]^a[B]^b
 Rate of forward reaction =Kf [A]^a[B]^b
 Rate of reverse  reaction proportional to [C]^c [D]^d
 Rate of reverse  reaction =Kr [C]^c [D]^d
 Where Kr and Kf are the rate constant for reverse and forward reactions respectively.
At equilibrium state
                                  Rate of forward reaction = Rate of reverse reaction
                         Kf [A]^a[B]^b = Kr [C]^c[D]d          
               
                        Kf / Kr  =[C]^c[D]^d / [A]^a[B]^b
                             
                       Kc=[C]^c[D]^d /  [A]^a[B]^b    IT IS KNOWN AS EQUILIBRIUM EXPRESSION

EQUILIBRIUM CONSTANT :-
                                                     Where Kc=Kf / Kr and is known as equilibrium constant.

UNIT:-

            The unit is mol/ dm^3.

Acid Rain

Defination :-
                      The rain having PH less than 5.6 Rain.

Explanation: -
                        Normal rain water is saturated with carbon dioxide.  It has PH of 5.6 however ; the acidity of rain greatly  increases in polluted areas during thunderstorm.Sulphur dioxide from power plants using fossil fuels and nitrogen oxides  from exhaust fumes of automobiles dissolve in rain water producing acids.
       2SO2 + O2 → 2SO3
Therefore,  during thunderstorms, the PH of rain water can be much lower because of sulphuric acid and nitric acids formed by lightening .This rain may have PH as low as 2.1. This value is lower than the PH of vinegar or lemon juice.
Sulphuric acid eats away metals to formvwater soluble salts and hydrogen
             Fe + H2SO4 →FeSO4 + H2
    Marble buildings and statues are slowly eroded by acid rain.
  CaCO3 + H2SO4 →  CaSO4 + H2O + CO2                 
Acid rain also kills fish, and destroys trees.Lakes and river may become too acidic for living things to survive.

Salts

                                  Salts
When hydrogen ion[H*] of an acid is completely or partially replaced by a metal the resulting substances is called as salt
       HCl→NaCl
H is a replaceable H atom thats why it is replaced by metal atom.

The first part of salt is meral ion and the second part is acid

NaCl
Na is metal ion
Cl is acid
Types of salts:-
There are three types of salts :
(1)Acidic salt
(2)Basic salt
(3)Neutral salt

Acidic Salt:-
A salt containing a replaceable H-atom or formed by partial neutralization of an acid is called as Acid salt.
Example:-
NaHCO3 ,KHCO3 ,NaHSO4

Basic salt:-
A salt containing replaceable OH-group or frmed by the partial neutralization of a polyhydroxy base is called as Basic salt.
Example:-
Zn(OH)2 ,Pb(OH)2

Normal Salt:-
A salt which is formed by the complete neutralization of an acid is called a Normal salt.
Example:-
Na2CO3 ,Na2SO4 ,K2CO3.

Simple Harmonic Motion

Simple  Harmonic Motion :-
        The type of vibratory motion  in which acceleration produce in a body is directly proportional to the displacement on either side of mean position and is always directed towards its mean position.
Mathematicaly:-
                            a proportional  -x
Conditions  of S.H.M :-

 (1)There must be elasticity in a body

 (2) Restoring force
 (3) Inertia
Example:-   

 (1)Mass spring  system
(2)Simple pendulum
(3) Ball and bowl system

Coulombs Law

LAW:-

The force of attraction or repulsion b/w 2 point charges is directly proportional to the product  of the magnitude of charges and inversely proportional  to the square of the distance  b/w them.

Mathematicaly:-
F proportional q1q2 -eq (1)
F proportional 1/r^2 -eq (2)
Combining  eq 1 and 2 we get
F=k q1q2/r^2

Here f is force q1 and q2 are charges and r is the distance taken in square.k is coulombs constant.
K:- The SI unit value of k is 9×10^9 Nm^2c^-2