Sarkar ki Blog

              Law of Conservation of Energy Energy can be transformed (or change) from one form to another. According to the law of conservation of energy : Whenever energy changes from one form to another, the total amount of energy remains constant.  In   other words, when energy change from one form to another, there is no loss or gain of energy. The total energy before and after transformation remains the same. Another definition of the law of conservation of energy is that : Energy can neither be created nor destroyed.               During the conservation of energy from one form to another, some energy may be wasted.  For example, when electrical energy is converted into light energy in an electric bulb, then some electrical energy is wasted in the form of heat.  Conservation of Energy During the Free Fall of a Body The sum of potential energy and kinetic energy of the ball remains the same a...

                                      Energy   if a person can do a lot of work we say that he has a lot of energy or he is very energetic. In physics also anything which is able to do work is said to possess energy. Thus, energy is the ability to do work.  For example, to cut a log of wood into small pieces, we have to raise the axe vertically above the log of wood and some work has to be done in raising the axe. If the axe is now allowed to fall on wood, it can do work in cutting the wood. Thus, the work done in raising the axe has been stored up in it, giving it the ability for doing work. The amount of energy possessed by a body is equal to the amount of work it can do when its energy is released. It should be noted that whenever work is done, energy is consumed. Energy is scalar quantity.   It has only magnitude but no direction.   Unit of Energy   ...

  The Principle of Flotation     When the weight of an object acting downwards is equal to the upward buoyant force exerted by the liquid, the buoyant  force will balance the weight of object due to which the object will float  in the liquid.  So, for an object to float in a liquid, the weight of object should be equal to buoyant force acting on it. But by Archimedes'  principle,  the buoyant force acting on an object is equal to the weight of liquid displaced by it. This condition gives us the principle of flotation which can be stated as follows.             According to the principle of flotation : An object will float in a liquid if the weight of object is equal to the weight of liquid displaced by it.  That is, for flotation :   Weight of object = Weight of liquid displaced                                     ...

                                                            Buoyancy The tendency of a liquid to exert an upward force on an  object place in it, is called buoyancy. In general, whenever an object (or body) is immersed in water (or any other liquid),it appears to lose some weight and feels lighter.                         Buoyant Force When in object is immersed in a liquid, it experiences an upward force.This upward force is called buoyant force. Thus, the upward force acting on an object immersed in a liquid is called buoyant force.  It is due to the upward 'buoyant force' exerted by a liquid that the weight of an object appears to be less in the liquid than its actual weight in the air.          ...

                              Pressure Pressure is the force acting perpendicularly on a unit area of the object. The effect of a force depends on the area of the object on which it acts. Please note that the weight of a body is also a force. And it is always act in the downward direction. The pressure depends on two factors :  1. Force applied, and  2. Area over which force acts.       The same force can produces different pressures depending on the area over which it acts. For example, when a force acts over a large area of an object, it produces a small pressure. But  if the same force acts over a small area of the object, it produces a large pressure.         Pressure  = Force                               Area The SI unit of measuring pressure is 'newtons per square me...

                                  MASS   The mass of a body is the quantity of matter (or material) contained in it.  Mass is a  scalar quantity which has only magnitude but no direction. The mass of a body (or object) is commonly measured by an equal arm balance. The S I unit of mass is kilogram  which is written in short form as kg.  A body contains the same quantity of matter wherever it be -weather on earth, moon or even in outer space. So, the mass of an object is the same everywhere. For example, if the mass of an object is 5 kilograms on the earth, then it will have the same mass of 5 kilograms even when it is taken to any other planet, or moon, or in outer space. Thus, the mass of a body (or object) is constant and does not change from place to place.  Mass of a body is usually denoted by the small 'm'. Mass of a body is a measure of inertia of the body ...

         Keller's Laws of Planetary Motion  Johannes Kepler was a 16th  century astronomer who established three  laws which govern the motion of planets (around the sun). These are known as Kepler's law of planetary motion. The same laws also describe the motion of satellite (like the moon) around the planet (like the earth ).  1.   Kepler's first law states that : The planet move around the sun, with the sun at one of the two foci of the elliptical Orbit.  This law means that the orbit ( or path) of a planet around the sun is an ellipse ( oval-shaped) and not an exact circle. An elliptical part has two foci, and the sun  is at  one of the two foci of the elliptical path ( foci is the plural of focus). 2. Kepler's second law states that : Eac h planet revolves around the sun in such a way that the line joining the planet to the sun sweeps over equal areas in equal interval of time.  ...

                             Newton's Laws of Motion     Newton has given three laws to describe the motion of bodies. These laws are known as Newton's Laws of Motion.  The Newton's laws of motion give a precise definition of force  and establish a relationship between the force applied on a body and the state of motion acquired by it. We will now  discuss these laws of Motion and consider some of their important applications. Let us  start with the first law of motion.             Newton's first law of motion Some of the bodies (or objects) around us are at rest, that is, they are stationary,  whereas others are in motion. Newton's first law describes the behaviour of such  bodies which are in a state of rest or of uniform motion in a straight line. According to Newton's first law of motion :  A body at rest w...

1. First Equation of Motion                 The first equation of motion is :   V = u + at. It gives the velocity acquired by a body in time t. We will now derive this first equation of motion.              Consider a body having initial velocity 'u'. Suppose it is subjected to a uniform acceleration 'a' so that after time 't' it's final velocity becomes 'v'. Now , from the definition of acceleration we know that :               Acceleration  = Change in velocity                                                       Time taken  Or   Acceleration  =    final velocity- Initial velocity                             ...

Physical Change       Those changes in which no new substances are formed, are called physical change. In a physical change the substances involved do not change their identity. They can be easily return to their original form by some physical process. This means that physical change can be easily reversed. The change in physical state, size and shape of a substance are physical changes.  Some common examples of physical changes are : melting of ice, freezing of water, boiling of water, condensation of steam, making a solution, glowing of an electric bulb and breaking of a glass tumbler. The physical changes are temporary changes which can be reversed easily to form the original substance.  For example the melting of ice to form water is a temporary change we can reverse this physical change easily by cooling water to form the original substance, ice. Some more examples of physical changes are Melting of ice; Melting of butter; Melting of...

Explanation about mixtures  A mixture is a substance which consists of two or more element or compounds not chemically combined together. For example, air is a mixture of gases like nitrogen, carbon dioxide, humidity, etc. The various gases of the air are not chemically combined with one another. Similarly gunpowder is a mixture of potassium nitrate,whereas brass is a mixture of Copper and Zinc. All the solutions are mixtures. For example, salt solution is a mixture of of common salt and water. The various substances present in the mixture are known "as constituent of the mixture" or "components of the mixture". Some of the examples of mixture are : Air, Salt solution, Sugar solution, Kerosene oil, Ink, Petrol, Lime water, Coal, Soil, Blood, Soap solution, Iron and sulphur mixtures, etc.     Copper sulphate solution is a homogeneous mixture  Types of Mixtures  Mixtures are of two types: 1. Homogeneous mixtures,  and  2. Heter...

  What is life? Life is a characteristic that distinguishes physical entities that have biological process, such is in signalling and self sustaining process, from those that do not, either  because they never had such functions and are classified as inanimate. How the life begin on earth? Microbial life forms have been and Discover on the earth that can survive and even thrive at extremes high and low temperature and pressure, and in condition of acidity, salinity alkalinity  and concentrations of heavy metals that would have been regarded is a lethal  just a few years ago. These discoveries include the wide  diversities near the sea floor ydrothermal vent system where some organisms live essentially on chemical energy in absence of Sunlight. Similarly environments may be present elsewhere in the solar system. Understanding the process that lead to life, however, is complicated by the action of Biology itself. Earth's atmosphere today bears little resemblance t...

What is Blog and Blog Posts? A blog is a website or part of a site that contains regularly updated content about one or multiple topics. The term is short for "web log," which means to log information on  a website. The content on ablog usually comes in the form of articles on individual web page called blog post.                             They can be used for anything that involves communicating for publishing information on the world wide web.common uses include teaching and educational and corporate use. Your blog can be personal diary, a project collaboration tool, a guide or any means of communicating and publishing information on the web. What are the types of Blog? Types of Blog are:- 1.  Personal Blog  2. Buissness B log 3. Professional Blog  4. Niche Blog  5. Reverse Blog  6.  Affiliate Blog 7.  Media Blog  8. Freelance Blog  ...