11 NCERT PHYSICS REVISION NOTES

Work, Energy and Power Top Formulae The Scalar Product A.B = AB cos θ The scalar product follows the commutative law A.B = B.A The scalar product follows the distributive law A. (B + C) = A.B + A.C  A. (  B) =  (A.B) Where  is a real number Work W = (F cos θ) d = f  d Kinetic energy KE = 1mv2  p2 2         2m The equivalence of mass and energy E = m c 2 Average power Pav  Wt Instantaneous power P  dW dt P = F  v Unit of power horsepower (hp) 1 hp = 746 W 1 kWhr = 1000 (watt) × 1 (hour) = 1000 watt hour = 1 kilowatt hour (kWh) = 10 3 (W) × 3600 (s) = 3.6 × 10 6 J For conservative force WAB. 1 = WAB. 2 For non-conservative force WAB. 1 ≠ WAB. 2 Potentia...

Physical World Top Concepts Ø Physics is the branch of science that deals with nature and the natural phenomenon that occur. Ø Physics has two domains—microscopic as well as macroscopic. The microscopic domain contains atomic, molecular and nuclear phenomenon, whereas the macroscopic domain includes phenomena taking place at the laboratory, terrestrial and astronomical scales. Ø Science has a great influence on technology. Some of the technological advancements which are governed by scientific concepts are given below. Technology Scientific concept Sonar Reflection of ultrasonic waves Rocket propulsion Newton’s laws of motion Aeroplane Bernoulli’s principle in fluid dynamics Steam engine Law of thermodynamics Optical fibres Total internal reflection of light Ø The physical world is governed by four fundamental forces. The four fundamental forces in nature are 1. Gravit...