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Must Practice Questions for CBSE Physics CLASS 12: Solved

We will publish here the portions one cannot afford to miss while preparing for the CBSE class 12  Physics Examination

The Chapters will be posted below. On Clicking the name of the chapter a new page will open. On that page there will be a set of collected questions. On clicking the questions, the complete solution to the questions will open.

Please note that this system is under preparation. We hope to complete this within a month. The link will be activated only after completing the project.

  1. ELECTROSTATICS
  2. CURRENT ELECTRICITY
  3. MAGNETIC EFFECTS OF CURRENT
  4. ELECTROMAGNETIC INDUCTION
  5. ALTERNATING CURRENT
  6. ELECTROMAGNETIC WAVES
  7. OPTICS
  8. DUAL NATURE OF MATTER AND RADIATION
  9. ATOMS AND NUCLEI
  10. ELECTRONIC DEVICES
  11. COMMUNICATION SYSTEMS

 

Where is electricity stored after it is generated but before it is supplied? (Chat Transcript from FaceBook)

Where is electricity stored after it is generated but before it is supplied?
    • Mahesh Sable Electrical power cannot be stored and,therefore,power plants must produce power as and when demanded.power stations r connected in parallel hence load is equally distributed,electric Power can be adjusted with help of step up or step down transformers.

       

    • Mathew Abraham Transformer does not increase power

       

    • Chitraja Rajan The demand for electricity varies randomly within a day itself…so there should be something which should be adjusted according to the demand.

       

    • Vishnu Mohan G huge capacitors? i think i read somewhere like this.

       

    • Rajat Sharma

      Hi All, the question is very smart, i think electricity stored before generation is stored in Water(DAM), Uranium Rods(Nuclear), HydroCarbons(Coal, GAS). Electricity can only store when it is in Direct Current format like in Batteries, Capacitor(its a very small time to store/release) Well there are many source where we can store electricity. When electricity is in demand then Power generation takes place within huge Alternators, this powers generation takes places in terms of Phase Shift between all the power Houses across the country, if this phase shift is disturb then power grid fails. after this the transformers come into picture so as to reduce Resistance loses.

       

    •  
    • Kannan Kannan Ps in my little knowledge electricity unable to store continuing process of generater get current
      >________________________________

       

    • Chitraja Rajan at the generation side electricity is high ac current ..if it is converted into dc then there should be large containers to store them and also need suitable convertors to convert it in either form every time

       

    • Mathew Abraham In modern generators, there are equipment to control the rate of flow of water and in turn rate of rotation as well as the power generated. SO, it is quite right to say that electricity is generated as and when required. When you switch on a device power generation also increases until it reaches maximum capacity. Thereafter we will get less power. Remember the low voltage we suffer during the evening when the power consumption is maximum a few seconds ago · Like

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Carbon Nanotubes to Store Solar Energy

MIT Researchers have developed a new solar thermal fuel that could store up to 10,000 times more energy than previous systems. The fuel consits os CNT modified with azobenzene. The finding is still in development stage.
Read more details at http://physicsworld.com/cws/article/news/46620

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Teachers can also join the site and start posting answers to the questions as well as taking part in online discussions at forums.

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www.plustwophysics.com is offering free help in physics for students upto plustwo. Students of classes IX X XI and XII will find the site extremely useful as it supplies stdymaterials, questionbank, previous question papers, sample papers and more.

Physics Syllabus for AIPMT 2011

SYLLABUS FOR PRELIMINARY AND FINAL EXAMINATION OF

ALL INDIA PMT/PDT ENTRANCE EXAMINATION 2011

PHYSICS

Unit : 1 Introduction and Measurement

What is Physics? Scope and excitement; Physics in relation to science, society and technology; Need for measurement of physical quantities, units for measurement, systems of units-SI : fundamental and derived units. Dimensions of physical quantities. Dimensional analysis and its applications. Orders of magnitude, Accuracy and errors in measurement – random and instrumental errors, Significant figures and rounding off the numbers.

Graphs, Trigonometric functions, Concepts of differentiation and integration.

Unit : 2 Description of Motion in One Dimension

Objects in motion in one dimension, Motion in straight line, Uniform and non-uniform motion, its graphical representation and formulae, speed and velocity, relative velocity, average speed and instantaneous velocity. Uniformly accelerated motion, velocity-time graph, position-time graph and their formulae. Relations for uniformly accelerated motion with examples. Acceleration in one-dimensional motion.

Unit : 3 Description of Motion in Two and Three Dimensions

Vectors and scalars quantities, vectors in two and three dimensions, vector addition and multiplication by a real number, null-vector and its properties. Resolution of a vector in a plane, rectangular components. Scalar and vector products. Motion in two dimensions, cases of uniform velocity and uniform acceleration-projectile motion, general relation among position-velocity-acceleration for motion in a plane and uniform circular motion. Motion of objects in three dimensional space (elementary ideas).

Unit : 4 Laws of Motion

Force and inertia, first law of motion. Momentum, second law of motion, impulse, examples of different kinds of forces in nature. Third law of motion, conservation of momentum, rocket propulsion. Equilibrium of concurrent forces. Static and kinetic frictions, laws of friction, rolling friction, lubrication, Inertial and non-inertial frames (elementary ideas).

Unit : 5 Work, Energy and Power

Work done by a constant force and by a variable force, unit of work, energy and power. Work Energy Theorem. Elastic and in-elastic collisions in one and two dimensions. Notions of potential energy, conservation of mechanical energy : gravitational potential energy, and its conversion to kinetic energy, potential energy of a spring. Conservative forces. Different forms of energy, mass-energy equivalence, conservation of energy.

Unit : 6 Rotational Motion

Centre of mass of a two-particle system, momentum conservation and centre of mass motion. Centre of mass of rigid body, general motion of a rigid body, nature of rotational motion, rotational motion of a single particle in two dimensions only, torque, angular momentum and its geometrical and physical meaning, conservation of angular momentum, examples of circular motion (car on a level circular road, car on banked road, pendulum swinging in a vertical plane). Moment of inertia, its physical significance, moment inertia of uniform bodies with simple geometrical shapes, parallel axis and perpendicular axis theorem (statements only), Comparison between translatory (linear) and rotational motion.

Unit : 7 Gravitation

Acceleration due to gravity, one and two dimensional motion under gravity. Universal law of gravitation, inertial and gravitational mass, variations in the acceleration due to gravity of the earth, statement of Kepler’s laws of planetary motion, orbital velocity, geostationary satellites, gravitational potential, gravitational potential energy near the surface of earth, escape velocity, weightlessness.