CBSE Pathshala

Natural   Resources: Anything in the environment ‘which can be used’ is called ‘natural  resource’. Natural resources include total natural environment that support human life and  contribute to the production of necessities and comforts to mankind. So natural resources  are the components of atmosphere, hydrosphere and lithosphere.  On the basis of abundance and availability, the natural resources are of two types:  (a) Inexhaustible  (b) Exhaustible.  (a) Inexhaustible. These are in plenty and cannot be exhausted by man’s consumption e.g., air, sand,  clay etc, affected by over-population of mankind.  (b) Exhaustible. These are limited and can get exhausted over a period of time. i.e., coal, petroleum  etc.  Management of Natural Resources A system of controlling the use of natural resources in such a way as to avoid their wastage and to use  them in the most effective way is c...

The word atom is derived from the Greek word “Atomos” which means indivisible. John Dalton modeled atoms as hard indivisible spheres. An Indian philosopher Maharishi Kanad, postulated that if we go on dividing matter ( padarth ), we shall get smaller and smaller particles. Ultimately, a time will come when we shall come across the smallest particles beyond which further division will not be possible. He named these particles Parmanu . Ancient Greek philosophers – Democritus and Leucippus suggested that if we go on dividing matter, a stage will come when particles obtained cannot be divided further. Democritus called these indivisible particles atoms (meaning indivisible). How and why elements combine and what happens when they combine. Antoine L. Lavoisier laid the foundation of chemical sciences by establishing two important laws of chemical combination. (a) The Law of conservation of mass was stated by Antoine L. Lavoisier as” Mass can neither be created nor destroye...

Central Public School,Samastipur And Sadhana Devi Vidyapith, Samastipur [Student Practice] Quadratic Equations  : Contents 1. Standard form of a quad. Equations:  ax 2 + bx + c = 0 (a ≠ 0) 2. Solution of the quadratic equations only real roots by  (a) Factorization           (b) Completing the square                 (c) Quadratic formula 3. Relationship between discriminant and nature of roots. if D > 0 => Real & Distinct Roots          if D = 0 => Real & Equal Roots        if D < 0 => No Real Roots 4. Problems related to day to day activities Learning Objective: To learn the following facts 1. A second degree Equation of the form ax 2 + bx + c = 0 where a, b, c are real numbers and a ≠ 0 are called quadratic eqn. 2. If ax 2 + bx + c = 0 equivalent to (x – a) (x – b) = 0 then x = a an...