C L A S S 8 Pearson IIT Foundation Series Physics Sixth Edition This page is intentionally left blank. C L A S S 8 Pearson IIT Foundation Series Physics Sixth Edition Trishna Knowledge Systems Copyright © 2017 Trishna Knowledge Systems Published by Pearson India Education Services Pvt. Ltd, CIN: U72200TN2005PTC057128, formerly known as TutorVista Global Pvt. Ltd, licensee of Pearson Education in South Asia. No part of this eBook may be used or reproduced in any manner whatsoever without the publisher’s prior written consent. This eBook may or may not include all assets that were part of the print version. The publisher reserves the right to remove any material in this eBook at any time. ISBN: 978-93-325-7902-6 eISBN: 978-93-325-3071-3 Head Office: 15th Floor, Tower-B, World Trade Tower, Plot No. 1, Block-C, Sector-16, Noida 201 301, Uttar Pradesh, India. Registered Office: 4th Floor, Software Block, Elnet Software City, TS-140, Block 2 & 9, Rajiv Gandhi Salai, Taramani, Chennai 600 113, Tamil Nadu, India. Fax: 080-30461003, Phone: 080-30461060 www.pearson.co.in, Email: [email protected] Brief Contents Preface xiii Chapter Insights xiv Series Chapter Flow xvi Chapter 1 Measurements 1.1 Chapter 2 Kinematics 2.1 Chapter 3 Dynamics 3.1 Chapter 4 Hydrostatics 4.1 Chapter 5 Wave Motion and Sound 5.1 Chapter 6 Heat 6.1 Chapter 7 Light 7.1 Chapter 8 Electricity 8.1 Chapter 9 Magnetism 9.1 Chapter 10 Electromagnetism 10.1 Chapter 11 Sources of Energy 11.1 This page is intentionally left blank. Contents Preface xiii CHAPTER 2 KINEMATICS 2.1 Chapter Insights xiv Introduction 2.2 Series Chapter Flow xvi Geometrical Representation of a Vector 2.3 Distance and Displacement 2.4 CHAPTER 1 MEASUREMENTS 1.1 Distance 2.4 Introduction 1.2 Displacement 2.4 Speed 2.6 Physical Quantities and their Units 1.2 Characteristics of a Unit 1.2 Instantaneous Speed 2.7 Average Speed 2.7 Fundamental Quantity 1.2 Derived Quantity 1.2 Uniform and Non-Uniform Fundamental Unit 1.3 Velocity 2.8 Derived Unit 1.3 Instantaneous Velocity 2.10 Definitions of Units 1.4 Acceleration 2.12 Measurement of Length 1.4 Equations of Motion 2.14 Metre Scale 1.4 Graphical Representation of Motion 2.15 Vernier Calliper 1.5 Displacement–Time Graph 2.15 Description of Vernier Calliper 1.6 Velocity–Time Graph 2.16 Observations to be Made 1.7 Practice Questions 2.17 Measurement of Area 1.7 Hints and Explanation 2.26 Measurement of the Area of a Leaf 1.8 Measurement of Volume 1.8 CHAPTER 3 DYNAMICS 3.1 Measuring Jar 1.8 Introduction 3.2 Measuring Flask and Pipette 1.8 Classification of Forces 3.2 Burette 1.8 To Determine the Volume of a Newton’s First Law of Motion 3.3 Single Drop of Water 1.8 Types of Inertia 3.4 Measurement of Mass 1.9 Mass 1.9 Mass and Inertia 3.5 Applications of Different Types of Balances 1.9 Friction 3.5 Measurement of Density and Factors Affecting Frictional Force 3.5 Relative Density 1.10 Types of Friction 3.5 Advantages of Friction 3.6 Practice Questions 1.11 Disadvantages of Friction 3.6 Hints and Explanation 1.20 Methods to Reduce Friction 3.6 viii Contents Streamlining 3.6 CHAPTER 4 HYDROSTATICS 4.1 Momentum 3.6 Introduction 4.2 Units of Momentum 3.7 Kinetic Theory of Matter 4.2 Newton’s Second Law of Motion 3.8 (cid:31)(cid:30) (cid:30) Thrust and Pressure 4.2 Derivation of F =ma 3.8 Thrust 4.2 Units of Force 3.9 Pressure 4.3 Relation Between Newton And Dyne 3.9 Fluid Pressure 4.5 Weight and Mass 3.10 Pressure at a Point Inside a Liquid 4.6 Difference between Mass and Weight 3.11 Laws of Liquid Pressure 4.7 Newton’s Third Law of Motion 3.11 Hare’s Apparatus 4.8 Principle of Conservation of Mass 3.12 Law of Conservation of Momentum 3.12 Atmospheric Pressure 4.9 Proving Law of Conservation of Momentum by Newton’s third Law 3.12 Measurement of Atmospheric Pressure 4.10 Rockets 3.14 Mercury Barometer 4.11 Fortin’s Barometer 4.13 Work 3.14 Aneroid Barometer 4.14 Units of Work 3.15 Advantages of an Aneroid Barometer Energy 3.15 Over a Simple Barometer 4.14 Various Forms of Energy 3.16 Disadvantages of the Aneroid Barometer 4.14 Effect of Altitude on Atmospheric Pressure 4.15 Centre of Gravity 3.16 Altimeter 4.15 Activity 3.17 Weather Forecast 4.15 Centre of Gravity of Regular Bodies 3.17 Centre of Gravity of an Irregular Lamina 3.19 Gas Manometer 4.15 Stability of Bodies 3.20 Lift Pump 4.16 Equilibrium of Bodies 3.21 Construction 4.16 Conditions for a Body to be in Equilibrium 3.21 Working 4.17 Practical Applications 3.23 Pascal’s Law 4.17 Simple Machines 3.24 Application of Pascal’s Law 4.18 Power (P) 3.24 Upthrust 4.19 Load (W) 3.24 Velocity Ratio (V.R.) 3.25 Archimedes’ Principle 4.20 Efficiency (η) 3.25 Relative Density 4.21 Levers 3.27 Determination of Relative Density or Load Arm 3.27 Specific Gravity of a Solid 4.22 Effort Arm 3.27 Determination of the Specific Gravity of a Liquid Using Archimedes’ Principle 4.22 Law of Levers 3.27 Floatation 4.24 Classification of Levers 3.27 Pulley 3.29 Hydrometers 4.25 Practice Questions 3.33 Principle of Hydrometer 4.25 Hints and Explanation 3.40 Types of Hydrometer 4.26 Contents ix Plimsoll Lines 4.28 CHAPTER 6 HEAT 6.1 Boyle’s Law 4.28 Introduction 6.2 Bernoulli’s Principle 4.30 Flow of Heat Energy and Explanation of Bernoulli’s Principle 4.31 Thermal Equilibrium 6.2 Surface Tension 4.31 Difference Between Heat Explanation for Surface Tension 4.32 Energy and Temperature 6.2 Practice Questions 4.34 Measurement of Temperature 6.3 Hints and Explanation 4.42 Units of Heat 6.3 Heat Capacity 6.4 CHAPTER 5 WAVE MOTION Advantages of High Specific Heat Capacity of AND SOUND 5.1 Water 6.6 Introduction 5.2 Conductors and Insulators of Simple Pendulum 5.2 Heat Energy 6.6 Laws of Simple Pendulum 5.3 Thermal Expansions in Solids 6.6 1st Law of Simple Pendulum 5.3 Measurement of Temperature and 2nd Law of Simple Pendulum 5.3 Thermometer 6.7 3rd Law of Simple Pendulum 5.4 Different Temperature Scales 6.7 Verification of Laws of Simple Pendulum 5.4 Construction of Celsius Thermometer 6.8 Wave Motion 5.5 Marking of Fixed Points 6.8 Transverse Waves 5.6 Relation Between Different Scales 6.9 Longitudinal Waves 5.7 Clinical Thermometer 6.10 Relation between Frequency (n), Clinical Thermometer 6.11 Time Period (T) and Wavelength (λ) 5.8 Six’s Maximum and Minimum Thermometer 6.11 Galileo’s Thermometer 6.12 Sound 5.8 Experiment to Verify that Vibrating Bodies Change of State 6.13 Produce Sound 5.9 Determination of Melting Point of Wax 6.13 Transmission of Sound 5.9 Determination of Melting Point of Ice and Boiling Point of Water 6.13 Longitudinal Nature of Sound Waves in Air 5.10 Experiment to Determine the Sound Requires a Medium for Propagation 5.10 Melting Point of Ice and Music and Noise 5.11 Boiling Point of Water 6.13 Musical Instruments 5.11 Latent Heat of Fusion 6.14 Stringed Instruments 5.11 Specific Latent Heat of Fusion 6.14 Percussion Instruments (Drum Instruments) 5.11 Latent Heat of Vapourization 6.14 Wind Instruments (Blow Type Instruments) 5.11 Effect of Pressure and Soluble Impurities 6.16 Practice Questions 5.13 Practice Questions 6.18 Hints and Explanation 5.20 Hints and Explanation 6.25