Education

  Sources of Energy Energy plays a huge factor in our lives, providing comfort, increasing productivity and allowing us to live the way we want too. Energy lights our cities, powers our vehicles, used in cooking, manufacturing etc. What is energy Crisis? An energy crisis occurs when we all have a great need of fuel or electricity but does not have enough amounts of them. For example, a large portion of the energy we use is derived from oil. Some experts claim that we will run out of oil in just a few decades. But why energy crisis occurs? When we use energy in its usable form like in cooking, we convert the form of energy and get our work done during the process. Since we cannot reverse the change involved in this process so we cannot get back the original usable form of energy. Due to this, it becomes important to think about energy shortage and the related energy crisis. Good Source of Energy It should give large amount of energy per unit mass. It should be easy to access. It sho...

  CBSE Class 10 Science Notes Chapter 13 Magnetic Effects of Electric Current Magnet:  Magnetic field and magnetic field lines, Magnetic field due to a current carrying conductor, Right hand thumb rule, Magnetic field due to current through a circular loop. Magnetic field due to current in a solenoid. Magnet is an object that attracts objects made of iron, cobalt and nickle. Magnet comes to rest in North – South direction, when suspended freely. Use of Magnets:  Magnets are used in refrigerators. in radio and stereo speakers. in audio and video cassette players. in children’s toys and; on hard discs and floppies of computers. Properties of Magnet A free suspended magnet always points towards the north and south direction. The pole of a magnet which points toward north direction is called north pole or north-seeking. The pole of a magnet which points toward south direction is called south pole or south seeking. Like poles of magnets repel each other while unlike poles of m...

  The second law of thermodynamics asserts that processes occur in a certain direction and that the energy has quality as well as quantity.The first law places no restriction on the direction of a process, and satisfying the first law does not guarantee that the process will occur. Thus, we need another general principle (second law) to identify whether a process can occur or not. Fig. above shows Heat transfer process can occur when and only when it satisfies both the first and the second laws of thermodynamics. The second law also asserts that energy has a quality. Preserving the quality of energy is a major concern of engineers. In the above example, the energy stored in a hot container (higher temperature) has higher quality (ability to work) in comparison with the energy contained (at lower temperature) in the surroundings. The second law is also used in determining the theoretical limits for the performance of commonly used engineering systems, such as heat engines and refrig...

  ZEROTH LAW OF THERMODYNAMICS It is the basic law of thermodynamics which defines the temperature. Zeroth law states that: “When a body A is in thermal equilibrium with a body B, and also separately with a body C, then B and C will be in thermal equilibrium with each other”. It is the basis of temperature measurement. THERMOMETRIC PROPERTIES In order to obtain a quantitative measure of temperature, a reference body is used, and a certain physical characteristic of this body which changes with temperature is selected. The selected characteristic is called the thermometric property, and the reference body which is used in the determination of temperature is called the thermometer. Variables which are used to determine the temperature is known as Thermometric property. (i) Constant Volume thermometer – From ideal gas equation For constant volume, P α T, So T= f(P) Only i.e. temperature is only dependent on pressure, thus for constant volume thermometer Pressure, P will be thermometri...

Friction:-  It is the force resisting the relative motion of two solid surfaces, fluid layers, and material elements sliding against each other. Or  It is the opposition offered by surfaces to be in directly contact. There are several types of friction:- Dry friction is a force that opposes the relative lateral motion of two solid surfaces in contact. For example:-  1. Tyres or Wheels against the Road. 2. Movements of solids over cemented floors.  

Force:-   It is defined as the acceleration to move the object from one position to another.                                     Or  The push or pull on an object with mass that causes it to change its velocity. Force is an external agent capable of changing the state of rest or motion of a body.                                        Force = Mass × Acceleration                                  F = m × a Where, the terms are denoted by the following alphabets:-                        Force = F                   Mass = m                   Acceler...