Si unit of heat energy

Introduction :

Heat: Heat is a form of energy. It gives the feeling of hotness and establishes its existence .The Sun is the natural source of heat and light. Heat light is required for the process of Photosynthesis. We need heat energy for our daily activities. Heat energy is necessary to heat water, to cook, to manufacture glass, cement, and iron in factories. The food we take provides heat energy to us.
Sun is the natural source of heat.

Abundant heat and light we get from the sun.Solar energy is necessary for all the activities on the earth.Can you tell how rain is formed?Due to heat.

Heat is a Form of Energy and its Units

How can we say that is form energy?Is there any basis for it ?Energy is the ability to do work.Energy can be converted from one from to another.If heat is a from of energy.,it should be able to to do work.It should also be possible to convert heat into other forms of energy.
Since heat is a form of energy,should not the units of heat be the same of energy?The international unit of heat is called joule.Another unit called calorie is also used as the unit of heat.How much heat is a calorie? The amount of heat required to raise the temperature of one gram of water by one degree Celsius is called calorie.

History of Joule

The international unit of heat(any other form of energy) is called joule in honor of the British scientist James pres cot Joule.joule was accepted as the international unit of heat in 1948.
Meaning of calorie:
It is the amount of heat needed to increase the temperature of 1KG of water by 1⁰c.

Laws of motion application

Newton's Laws of Motion - First Law Of Motion
Newton's Laws of Motion - Examples Of The First Law
Newton's Laws of Motion - Second Law Of Motion

The Newton first law of motion concentrates on a state of constant motion but adds unless an outside influence, force, acts on it. Force produces a change in the state of motion (velocity describes a body's motion); that is, an acceleration. Newton found that the greater a body's mass the greater the force required to overcome its inertia and mass is taken as a quantitative measure of a bod…

Newton's Laws of Motion - Applications Of The Second Law

For objects thrown upward, gravitational acceleration is still 32 ft/sec/sec downward. A ball thrown upward with an initial velocity of 80 ft/sec has a velocity after one second of 80-32= 48 ft/sec, after two seconds 48-32= 16 ft/sec, and after three seconds 16-32= -16 ft/sec (now downward), etc. At 2.5 seconds the ball had a zero velocity and after another 2.5 seconds it hits the ground with a ve…

Newton's Laws of Motion - Third Law Of Motion Or Law Of Action-reaction
Newton questioned the interacting force an outside agent exerted on another to change its state of motion. He concluded that this interaction was mutual so that when you exert a force on something you get the feeling the other is exerting a force on you. Newton's third law of motion states: When one body exerts a force on a second body, the second body exerts an equal and opposite force on …

Newton's Laws of Motion - Examples Of The Third Law
(1) What enables us to walk? To move forward parallel to the floor we must push backward on the floor with one foot. By the third law, the floor pushes forward, moving us forward. Then the process is repeated with the other foot, etc. This cannot occur unless there is friction between the foot and floor and on a frictionless surface we would not be able to walk. (2) How can airplanes fly at high a…

Read more: Newton's Laws of Motion - First Law Of Motion, Examples Of The First Law, Second Law Of Motion, Applications Of The Second Law http://science.jrank.org/pages/4658/Newton-s-Laws-Motion.html#ixzz0paAGxF7r

Sir Isaac Newton three Laws of Motion

Introduction :
In 1684, encouraged by his friend Edmund Halley, Sir Isaac Newton embarked on writing what was to be The principia mathematica was one of the greatest scientific works ever published. He enunciated the three laws of motion and the universal law of gravitation, which explained all the three Kepler's laws of planetary motion.
                    
In earlier times, motion of bodies was studied by philosophers. Most philosophers believed that a body moved with uniform velocity due to some external agent. They also thought that if there were no external agent the body would naturally come to rest. Galileo was the first to show that some external force was necessary to change the velocity of a body but that no external force was necessary to maintain the velocity of a body. This principle was adopted by Newton in his first law of motion.

Sir Issac Newton first law:

    The law enables us to define inertia and force. From this law it can be concluded that if the net external force on an object is zero, the acceleration of the object is zero.
Inertia ; If the net external force is zero, a body at rest continues to be at rest and a body in motion continues to move with uniform velocity. This property is called inertia. It is the resistance to change the state of uniform motion. Mass is a measure of inertia.  Ex: when the bus stops suddenly our feet stop due to the friction. But the rest of the body continues to move forward due to inertia of motion.
Force :  It is the physical quantity that changes or tries to change the state of rest or of uniform motion along a straight line.

Sir Issac Newton second law:

By Newton first law of motion, when there is no net external force on a body it moves with uniform velocity. In terms of momentum, the body will have constant momentum when there is no net external force on a body, Hence, when the momentum of a body changes the body must be under the action of a net external force.
           
Newton's second law of motion states that " The rate of change of momentum of a body is directly proportional to the resultant or net external force action on the body and takes place in the direction  in which the force acts" .
            
A body of mass m moving with velocity v is under the action of a net external force F in the direction of velocity. If its velocity is increased by `Deltav` in a time interval `Deltat`  then by the second law
                                                  F `prop` dp /dt             (or)                   F  `prop` d/dt (mv)        (since p = mv)
                               F = k d/dt (mv)                    , Assuming that the mass of the body is constant
                   F = k m dv/dt  =  k m a    , which shows that the net force is proportional to the product of mass and acceleration.
              
The proportional constant k is made equal to one, by properly selecting the unit of force. The SI unit of force is newton which is defined as the force that causes an acceleration for 1 ms^-2 on a body of mass 1 kg. Substituting k = 1 in F = k m a ,  we get
                                                    F  =  m a .
               The dimensional formula of force is [MLT^-2] .

Sir Issac Newton third law:

Newton's third law tells us about the origin of the force that causes acceleration. It states that " to every action, there is always an equal and opposite reaction " .
                     
In this statement, action and reaction are nothing but forces. When we hit a wall we apply  some force on the wall. An equal and opposite force acts on us due to the wall at the same instant of time. When we walk on the road we push the road backward and the road applies an equal and opposite force on us so that we can move forward. Newton's third law is not strictly applicable when the interaction between two bodies separated by a large distance is considered.

Newtons theory

NEWTON'S LOW OFUNIVERSAL GRAVITATION:-
The mechanisms of Newton's law of universal gravitation; a point mass m₁ attracts another point mass m₂ by a force F₂ which is proportional to the product of the two masses and inversely proportional to the square of the distance (r) between them. Regardless of masses or distance, the magnitudes of |F₁| and |F₂| will always be equal. G is the gravitational constant.

Newton's law of universal gravitation states that every massive particle in the universe attracts every other massive particle with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. (Separately it was shown that large spherically-symmetrical masses attract and are attracted as if all their mass were concentrated at their centers.) This is a general physical law derived from empirical observations by what Newton called induction.^[1] It is a part of classical mechanics and was formulated in Newton's work Philosophiae Naturalis Principia Mathematica ("the Principia"), first published on 5 July 1687. (When Newton's book was presented in 1686 to the Royal Society, Robert Hooke made a claim that Newton had obtained the inverse square law from him – see History section below.) In modern language, the law states the following:

Every point mass attracts every single other point mass by a force pointing along the line intersecting both points. The force is directly proportional to the product of the two masses and inversely proportional to the square of the distance between the point masses:^[2]

where:

·         F is the magnitude of the gravitational force between the two point masses,

·         G is the gravitational constant,

·         m₁ is the mass of the first point mass,

·         m₂ is the mass of the second point mass, and

·         r is the distance between the two point masses.

Lorentz force

Proof of Faraday's Law
It is evident from Faraday's experiments that whenever there is a change in the magnetic flux passing through a closed circuit, an electric current is induced in the circuit. It can be explained on the basis of Lorentz force.

Suppose a conducting-rod JK (Fig. 7) is being moved without friction on the arms of a U-shaped stationary conductor MNOL with a velocity v towards right. The conductor is situated in a magnetic field B perpendicular to the plane of paper directed downwards. Due to the motion of the conducting-rod, the free electrons present in the rod are acted upon by a magnetic (Lorentz) force F_m of magnitude qvB which takes the electrons from the end J of the rod to the end K. Since a closed circuit is available to the electrons, they drift along the path J-*K-*O^N-*J. Thus, an electric current is established in the circuit along J->N->0->K-*J (anticlockwise)*. So long the rod JK is kept moving in the magnetic field, the electric current continues to flow in the circuit. It means that an emf is induced in the moving rod which maintains the current in the circuit. Since this emf induced in the rod is due to the motion of the rod, it is also called as the 'motional emf. It is due to the Lorentz forces acting on the free electrons in the moving rod.

Suppose, the induced emf in the moving rod JK is e and the induced current in the circuit is i. We know that when a current-carrying conductor is in a magnetic field, it is acted upon by a force in a direction given by the Fleming's left-hand rule. The magnitude of the force imposed by the magnetic field B on the current-carrying rod JK is given by
F' = i IB,

where I is the length of the rod JK. The force F*' is directed towards left. Hence, to keep the rod moving with a constant velocity v towards right, a force F equal and opposite to F' will have to be applied on it; that is
F = -F' = -ilB.

Suppose, under the force Ft the rod JK undergoes a displacement Ax* in the direction of the force in a time-interval At and comes in the position J 'K'. Then, the work done on the rod will be given by
W =F*.Ax*= F Ax = -HB Ax. But A* = v x Af (magnitude of velocity x time-interval).
W = -HBvAt.
But i x At = q (charge flown through the circuit in time At)
W = -Bvlq.

This work provides the necessary energy for the flow of charge in the circuit. We know that the energy supplied by a cell in flowing unit charge through a circuit is called the emf of the cell. Hence the induced emf e in the rod / K (which is working as a cell in the circuit J N O K J) is given by
e = W/q = - Bv I. ...(i)

In the time-interval At, the area of the circuit increases from JNOKJ to J' N O K' JHence, during this time-interval, the change in the magnetic flux passing through the circuit is given by
A<P_b = magnitude of magnetic field x change in area (JJ 'K'K) = B x (I x Ax).

Hence the rate of change of magnetic flux is
AO_fl Ax
I — O I ~~ .
At At
But Ax/At = v (velocity of the rod). Thus
-tf'Blv. ...(ii)
Comparing eq. (i) and (ii), we get
A<D_fl
^{e =} -~AT■
In the limit At —» 0,
d<b_B
^{e =} ~~dT■

This is Faraday law of electromagnetic induction.

The negative sign signifies Lenz's law. The direction of current (anticlockwise) in the circuit due to the induced emf e is such that the force imposed on the rod (due to the current) opposes the motion of the rod (the motion of the rod is the cause of the current).

It can be seen in the other way also. The direction of current in the circuit is such that the magnetic field produced due to this current is just opposite to the original field B. That is, it opposes the increase in the magnetic flux passing through the circuit (the increase in the magnetic flux is the cause of the generation of current). We may see it from any point of view, the direction of the induced current is always such that it opposes the very cause of its production. This is Lenz's law.

Dimensions of Induced E.M.F.: Numerically, we have
d<b_B ^{e =} ~dT-
, dimensions of e = ₌ ^T^A'*] _{= a} , _A_,
dimensions of t [T]

Organic chemistry articles

Introduction:-
The study of chemistry of carbon compounds is called organic chemistry. According to Lavoisier that all compounds obtained from vegetables and animal sources always contained carbon and hydrogen mainly and nitrogen and phosphorous are also found in some compounds. According to Berzilius organic compounds  are produced from plant and animals only due to presence of some vital force in them.It is called  “Vital force theory”.It is disproved by wholer by producing urea(NH₄ CONH₂) from ammonium cyanate (NH₄CNO)
                                                                 NH₄CNO→ NH₄ CONH₂  
                                   Kolbe synthesized acetic acid (CH₃COOH) from its elements.

Compounds:-

Carbon form millions of compounds due to the following reasons.
1.    High catenation
2.    Tetravalency
3.    Ability to form multiple bonds
4.    Ability to exhibit isomerism

Classification of organic compounds based on carbon skeletion
                     Carbon compounds
Open chain(acyclic)                 (cyclic) closed chain
Aliphatic
Saturated    Unsaturated

Alkanes        Alkenes    Alkynes
Alkanes: Open chain compounds with single bonds between carbon atoms
Ex:  methane and ethane
Alkenes: open chain compounds with atleast one double bond in the carbon chain
Ex: ethylene,propylene
Alkynes: open chain compounds with atleast one triple bond in the carbon chain
Ex:  acetylene,propylene
Alicyclic: Carbon ring with single bond between carbon atoms
Ex: Cyclohexane C₆H₆
Aromatic: planar ring structures with (4n+2)∏ electrons  are called aromatic  according to Huckel rule.Where n is 0,1,2,….
    Ex: pyridine,Furan.

Classification of Carbon compounds on the basis of functional groups:-

Atom or bond or group of atoms in a molecule which is responsible for the characteristic properties of the compound is called functional group

Name	General Formula	Name	Structural Formula
Alkanes	CnH2n+2	Ethane
Alkenes	CnH2n	Ethene
Alkynes	CnH2n-2	Ethyne

Natural Organic Soap

Introduction :
Soap is made by heating animal or vegetable oils with sodium hydroxide. Esters present in fats are broken down to glycerol and sodium salt of fatty acid.

Fat + Sodium hydroxide ------------> Soap + Glycerol

This reaction is called saponification.
Let us discuss the cleaning action of natural organic soap in detail:

Cleaning Action of Natural Organic Soap

The cleaning action of natural organic soap depends on its structure.
E.g. Sodium stearate consists of a long hydrocarbon chain which is hydrophobic (water-hating), attached to an ionic head, which is hydrophilic (water - loving). These molecules dissolve in water because of ionic end to the molecule.

When dissolved in water, the soap molecules lower the surface tension of the water, makiang it wet objects more easily. The molecules also interact with grease and dirt present in the cloth. The hydrophobic hydrocarbon chain is attracted to the grease and become embedded in it. The hydrophilic head of molecule points away from dirt and is attached to water molecule. When water is agitated, the grease is released from the cloth fibre or dish and is completely surrounded by soap molecules. Rinsing with fresh water removes this grease. The use of soap in hard water creates lots of problems because it forms scumbs with hard water. But nowadays synthetic detergents are available which do not scumb witrh hard water. Sodium alkylbenzene - sulphonates were developed in 1970s.

They have a similar long hydrocarbon chain to soap molecules, but the ionic group at hydriphilic head has been changed. The early synthetic detergent molecules were not biodegradable and cause pollution problems in rivers and streams.

Uses of Natural Organic Soap:

• Natural organic soap can be used to avoid or reduce many skin problems.
• Its ingredients have been produced without using fertilizers or pesticides, so it is not harmful to the skin.
• It leaves our our skin feeling clean and moisturised.
• Glycerine, which is a great moisturizer is retained by the natural organic soaps.
• Reduction in the use of toxins helps to create better living environment.
• Most of them are also free from animal fats, which prevents the killing of animals.