# Physics Textbook

Energy is a precious commodity. It keeps a nation alive. It runs industries, transport, and communication facilities. It provides us conveniences in daily living. The radio, television, light fixtures, stove, water pump and other devices, and appliances require energy to function.
The unifying theme of this module is energy—its many forms and the changes it undergoes. This module discusses the importance of energy in the different aspects of daily living. The content is divided into the following units:
Unit I, Energy and Society, discusses the different views of physics—as a discipline and its relation to the other science disciplines, the activities of physicists and how their work relate to the developments in science and technology, and how physics interrelates with technology and society.
Unit II, Energy in the Environment, starts with light, a form of energy that we are familiar with. The behavior of light as it interacts with materials is presented in the context of light and vision. Everyday situations are used to advantage to describe the properties of light. Nuclear radiation, a form of energy other than sunlight, is the other theme included in this unit. The discussion shows the benefits derived from and the environmental hazards of nuclear energy.
Unit III, Energy in the Home, focuses on the use of electrical energy in the household. Concepts are discussed with the circuitry in the house as the starting point. The transformation of electrical energy to other forms, electrical energy consumption, and how to use energy wisely are given emphasis. The benefits derived from and dangers posed by the use of electrical energy conclude the unit.
Unit IV, Energy and the Economy, gives importance to the transformation of other forms of energy to electrical energy as it describes electrical energy generation, transmission, and distribution. Electromagnetic forces and electromagnetic induction are the major concepts of the unit.
The module features simple laboratory activities requiring readily available materials. Some activities are investigatory. Others are verifications. Some are meant to guide you in analyzing abstract ideas or experimental data. Some activities may be done at home. Doing the activities will concretize or operationalize certain physics concepts to enhance your understanding of the theories involved. It will also help you acquire analytical skills and familiarity with the science processes, which in turn will help you in decision-making.
The questions and problems in the study guide will help you integrate the main ideas discussed in each chapter.
I hope that this module will help you become more aware of the relevance and importance of science, particularly physics, and technology in your everyday life.

## Table of Contents

Unit I Energy and Society
Chapter 1 Physics, You, and Society
* Physics is a Way of Thinking
* Physics is the Pioneer Science
* Physics in a Personal and Social Context
* Summary
Unit II Energy in the Environment
Chapter 2 Light and Sight
* The Human Eye
* Light
* The Colors of Objects
* Blue Sky, Red Sunset, and White Clouds
* Color Vision
* Summary
Chapter 3 Reflection and Mirrors
* Plane Mirrors
* Curved Mirrors
* Summary
Chapter 4 Lenses and Vision
* Refraction of Light
* Trapping Light
* Lenses
* Image Formation by Lenses
* The Camera and the Eye
* Vision Defects and the Corrective Lenses
* Aids to the Human Eye
* Summary
Chapter 5 Radiation Around Us
* A Century with Radioactivity
* Natural and Artificial Isotopes
* Changing Identities: Nuclear Transformation
* Living with Radiation
* People and Ionizing Radiation
* Radiation Applications
* Summary
Chapter 6 Reactors and Nuclear Energy
* Mass Defect and Binding Energy
* Fission
* The Power of Nuclear Reactors
* A Natural Nuclear Reactor
* Environmental Hazards from a Nuclear Reactor
* Fusion in the Stars
* Summary
Unit III Energy in the Home
Chapter 7 Electric Circuits
* House Wiring
* Simple Electric Circuit
* Electric Current
* Voltage
* Conductors or Insulators
* Current, Voltage, and Resistance: Ohm's Law
* Factors Affecting the Resistance of a Wire
* Electrical Connections
* Summary
Chapter 8 The Benefits and Dangers of Electrical Energy
* Matching Source and Load
* Power Rating of Appliances
* Heat Generated in Appliances
* Short Circuit and Overload
* Circuit Protector
* Electrical Energy Consumption
* Energy Saving
* Electric Current and the Human Body
* Electrical Hazards and Safety
* Summary
Unit IV Energy and the Economy
Chapter 9 The Magnet and Current Connection
* Oersted and the Magic of Magnetism
* From Magnets to Motors
* Painting Pictures with Magnets
* Summary
Chapter 10 Power Generation, Transmission, and Distribution
* Power Plants
* In Search of the Magnetic-Induced Current Connection
* Electromagnetic Induction
* Lenz's Law
* Faraday's Dynamo
* Electrical Energy Transmission and Distribution
* Power Losses
* Superconductivity
* Summary
Unit V Energy and Transportation
Chapter 11 Going Places
* Describing Motion
* Average Speed
* Acceleration
* Falling Body
* Graphing Motion
* Speed and Velocity
* Acceleration and Velocity
* Moving On: Rapid and Mass Transport
* Summary
Chapter 12 What Causes Motion
* Early Studies on Causes of Motion
* Net Force
* The Law of Inertia
* The Law of Acceleration
* The Law of Interaction
* Impulse and Momentum
* Conservation of Momentum
* Friction and Streamlining
* Force: The Cause of Motion
* Summary
Chapter 13 Conservation of Energy
* Energy Transfer
* Kinetic Energy
* Potential Energy
* Conservation of Mechanical Energy
* Power and Efficiency
* Heat and Work
* Thermal Energy
* Heat Engines
* Law of Conservation of Energy
* Energy Conservation Process: The Second Law of Thermodynamics
* Light Energy
* Summary
Chapter 14 Floating and Flying
* Pressure
* Applying Fluid Pressure
* Buoyancy in Liquid
* Safety at Sea
* Buoyancy in Air
* Summary
Unit VI Energy and Information and Communication Technologies
Chapter 15 Sound in Communication
* Contributors to the Development of the Telephone
* The Nature of Sounds
* Characteristics of Sound Waves
* Properties of Sound Waves
* The Beginning of Electric Communications
* The Telephone System
* Summary
Chapter 16 Wireless Communication
* The Beginning of Wireless Communication
* Radio Communication
* Telecommunication Links
* Energy Conservation in Communication
* Summary
Chapter 17 Electronics
* Early Development in Electronics
* Semiconductors
* Discrete Electronic Components
* Integrated Circuits
* Optoelectronic Components
* Putting Electronics to Work
* Summary