ACE EDUCATION PHYSICS O’LEVEL Grade 10 − 12 GCSE, GCE NSWANA CHING’AMBU The Authorship and Career Network authorshipandcareernetwork@gmail.com +260976008283, +260972719373 i The Authorship and Career Network ‘Impossibility Our Possibility’ The Authorship and Career Network is an organisation with a sole objective of promoting excellence in research, literacy, scholarship, education and skill development by supporting authors in Africa and beyond to publish their works. Published for Africa by The Authorship and Career Network Indeco House, Cairo Road, Lusaka, Zambia. Copyright © 2021 by Nswana Ching’ambu All rights reserved. No part of this publication may be reproduced, stored or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise without written permission from the publisher.
It is illegal to copy this book, post it to a website, or distribute it by any other means without permission. Nswana Ching’ambu asserts the moral right as an author First edition ISBN: 978-9982-913-18-8 ii To the students Ace Education Book Series aims at giving detailed material in the simplest way to help students understand and recall information easily. The books also highlight the importance and application of each topic in real life so that students can understand why they are learning the material, how the material relates to or can be used in real life. Ace Education Physics O’level consists of 33 units.
Each unit begins with the introduction and overview of the unit, and ends with the review questions and solutions. To fully benefit, students are advised to cover everything in each unit considered. Students can also learn more from our social media platforms. On these platforms, students can find additional information, ask questions or participate in helping other students.
With full confidence, this book will help a number of students, not just by boosting their scores, but also to understand Physics Ordinary Level. Ace Education About the author Nswana Ching’ambu has a bachelor’s degree in Human Biology from the University of Zambia and Teaching Methodology from Gideon Robert University. He has been lecturing Clinical Medicine courses at Gideon Robert University for many years. He lectures Anatomy and Physiology, Medical Biochemistry and Nutrition, and previously used to lecture Cellular Pathology and Basic Microbiology.
He is the founder of Ace Education and the author of Ace Education Book Series for O’Levels: Biology, Chemistry, Physics and Mathematics.com cnswana@hotmail.com aceeducationbooks@gmail.com iii TABLE OF CONTENTS UNIT 1: MEASUREMENTS…………………………………………………………………………….1 UNIT 2: SCALAR AND VECTOR QUANTITY…………………………………………………….18 UNIT 5: MASS AND WEIGHT…………………………………………………………………….23 UNIT 6: VOLUME AND DENSITY…………………………………………………………….………30 UNIT 7: CENTRE OF GRAVITY………………………………………………………………………….37 UNIT 8: DISTANCE AND DISPLACEMENT………………………………………………….…………42 UNIT 9: SPEED AND VELOCITY……………………………………………………………….49 UNIT 11: MOTION GRAPH…………………………………………………………………….……………64 UNIT 13: CIRCULAR MOTION…………………………………………………………….73 UNIT 14: FORCE ACTING ON SPRING………………………………………………………….75 UNIT 15: MOMENT OF A FORCE…………………………………………………………….…………78 UNIT 16: WORK, ENERGY AND POWER…………………………………………………….82 UNIT 17: SIMPLE MACHINE…………………………………………………………………………….105 UNIT 19: THERMAL PHYSICS……………………………………………………………….…………120 UNIT 20: TRANSFER OF THERMAL ENERGY…………………………………………….137 UNIT 21: HEAT ENERGY AND LATENT HEAT…………………………………………….………147 UNIT 22: WAVE MOTION………………………………………………………………………….……154 UNIT 23: ELECTROMAGNETIC SPECTRUM…………………………………………………….167 UNIT 25: SOUND WAVE………………………………………………………………………….…190 UNIT 27: ELECTROMAGNETIC INDUCTION…………………………………………………. 198 UNIT 28: STATIC ELECTRICITY…………………………………………………………………. 208 UNIT 29: CURRENT ELECTRICITY……………………………………………………….214 UNIT 30: PRACTICAL ELECTRICITY……………………………………………………………….231 UNIT 31: BASIC ELECTRONICS……………………………………………………………………….241 UNIT 32: ATOMIC STRUCTURE………………………………………………………………….251 UNIT 33: RADIOACTIVITY………………………………………………………………………………257 iv 1.0 MEASUREMENTS Introduction Everything around us is made up of matter. This book, your pen, clothes, shoes, food, a wire, a car, an airplane, petrol, diesel, water and so on, are all matter.
Some matter such as petrol, diesel and food store energy. When petrol is burnt it releases energy. How does this energy interact with matter? For instance, burning petrol in a car engine. The study of matter, energy and their interaction is called physics.
In simpler terms, physics is the study of how things around us work. For example, how a car moves, an airplane flies, an electric bulb lit, a speaker works and so on. Matter has different sizes. The size of this book is different from that of a pen, cellphone, computer, car, etc.
Therefore, to understand how things around us work, we need to have precise measurements of each object we study. To have exact measurements, objects have to be measured. A physical quantity is anything that can be measured. Length, time and temperature are few examples of things that can be measured and therefore are physical quantities.
When we measure an object, we obtain its size. However, size alone is not sufficient. Imagine you go to buy a carpet for your room. Can it be adequate to say, “I need 5 carpets.” Likely not! Therefore, to describe a physical quantity such as length, not only the size is needed but also the unit.
For example, 5 metres of carpet, 50 kilometre journey, 2 kilograms of sugar, 5 litres of cooking oil, 37 oC (degree celcius), 10 hours 30 minutes and so on. Specific outcomes This unit covers the types of physical quantities, standard units and the importance of prefixes. By the end of this unit, you will be able to: ❖ Define physics ❖ Define the following physics terminologies: • Physical quantity • Magnitude • Unit ❖ State the seven base quantities ❖ Give examples of derived quantities ❖ Differentiate base and derived quantities ❖ Understand what SI units are ❖ State the seven SI units with their symbols ❖ Understand what prefixes are and how to use them Measurements 1 MEASUREMENTS 1.1 QUANTITY • Physics is the study of matter, energy and their interaction. • It deals with physical quantities and motions of matter.
• A physical quantity is a quantity that can be measured. It is expressed by a magnitude with a suitable unit. • Magnitude is the size of a quantity, for example, 2, 150, 3, 10. • Unit is the standard measure of a quantity, for example, s (second), m (metre), kg (kilogram).
❖ TYPES OF PHYSICAL QUANTITIES 1. BASE QUANTITY • Base quantities are fundamental physical quantities. • These quantities contain only one unit. • There are seven base quantities: length, mass, temperature, time, current, amount of substance, and luminous intensity.
DERIVED QUANTITY • Derived quantities are quantities that consist of two or more base quantities. • Therefore, they have a combination of units. • For example, speed is a derived quantity. Speed is the total distance covered per unit time.
Therefore, it consists of two base quantities; length (distance covered) and time. Types of physical Base quantities Derived quantities quantities Examples Length Volume Time Density Mass Speed Temperature Area Current Force Amount of substance Pressure Luminous intensity 1.2 UNITS • Unit is defined as the standard measure of a quantity. • SI units (International System of the unit) are used as standardized units of measurements. • There are seven SI units.
• The table below shows SI units and their symbols. Base quantities SI unit Symbol Length Metre m Time Second s Mass Kilogram kg Temperature Kelvin K Current Ampere A Amount of substance Mole mol Luminous intensity Candela cd 2 Measurements 1.3 PREFIXES • Prefixes are multiples or decimals of ten. • They are useful for expressing the size of physical quantities that are too large or small. • The table below shows the common prefixes.
Prefixes Value Form Symbol Mega 1 000 000 106 M Kilo 1 000 103 K centi 0.000 000 001 10−9 n Measurements 3 REVIEW QUESTIONS 1. What is physics? A. The study of numeral values and their operation. The study of matter, its composition, properties and interaction to form other substances.
The study of matter, energy and their interaction. The study of living things. Physics as a field of science deals with A. properties of matter.
how matter forms a living thing. physical quantities of matter and its motion. all the above. Magnitude is defined as A.
property of the physical quantity. quality of the physical quantity. standard measure of the physical quantity. size of the physical quantity.
Unit is defined as the A. Property of the physical quantity B. Quality of the physical quantity C. Standard measure of the physical quantity D.
Size of the physical quantity 5. All physical quantities have A. Magnitude and unit B. Magnitude and size C.
Quantity and quality D. Quality and unit 6. Which of the following consists of base quantities. Length, mass and speed B.
Length, mass and time C. Time, mass and density D. Mass, volume and speed 7. The following consists of derived quantities A.
Length, mass and speed B. Length, mass and time C. Time, mass and density D. Force, volume and speed 8.
The SI unit of time is A. The SI unit of mass is A. The SI unit of length is A. The SI unit of temperature is A.
The SI unit of current is A. The SI unit of amount of substance is A. The SI unit of luminous intensity is A. Which of the following value is the same as 1000 seconds? A.
106 ms Measurements 5 SOLUTIONS 1.0 SCALAR AND VECTOR QUANTITIES Introduction Imagine you walked 50 m to the right and walked back 40 m to the left. What is the total distance you covered? It’s 90 m (50 m + 40 m). How far are you positioned from the starting point? 10 m (50 m − 40 m). Why is there a difference between the first question and the second question? The first question asked only about the size of the distance covered.
However, the second question asked about the size of distance and direction moved in relation to the starting point. In physics, quantities that consider only the size are called scalar quantities while quantities that consider both the size and direction are called vector quantities. Specific outcomes This unit covers scalar and vector quantities. By the end of this unit, you will be able to: ❖ Scalar quantity: • Define a scalar quantity • Give examples of scalar quantities ❖ Vector quantity: • Define a vector quantity • Give examples of vector quantities • Differentiate scalar quantities and vector quantities • Calculate addition and subtraction of vectors Scalar and Vector Quantities 7 SCALAR AND VECTOR QUANTITIES 2.1 SCALAR QUANTITY • A scalar quantity is a quantity that only has magnitude but no direction.
• Scalar quantities are indicated only by the size of the quantity. • Examples of scalar quantities are length, time, mass, volume, density, distance, speed, area, pressure, work and temperature.2 VECTOR QUANTITY • A vector quantity is a quantity that has both magnitude and direction. • Vector quantities are indicated by the size and the direction of motion of the quantity. • Examples of vector quantities are displacement, velocity, acceleration, weight, gravity, and force.3 ADDING VECTORS QUANTITIES • When adding vector quantities, consider both the magnitude and direction of motion of the quantity.
• If both vector quantities are moving in the same direction, the resultant vector is the sum of all vectors. VR = V1 + V 2 where VR is the resultant vector V1 and V2 are individual vectors moving in the same direction • If vector quantities move in the opposite direction, the resultant vector is the difference between the forward and backward vectors. VR = V1 – V 2 where VR is the resultant vector V1 and V2 are individual vectors moving in the opposite direction ❖ EXAMPLES Find the resultant vector of the following forces ❖ SOLUTIONS 1. VR = V1 + V2 − V3 = 3N + 1N − 3N = 1N 8 Scalar and Vector Quantities REVIEW QUESTIONS 1.
What is a scalar quantity? A. A quantity that can be measured B. A quantity that has both magnitude and direction C. A quantity that has a unit D.
A quantity that only has magnitude but no direction 2. What is a vector quantity? A. A quantity that can be measured B. A quantity that has both magnitude and direction C.
A quantity that has a unit D. A quantity that only has magnitude but no direction 3. A quantity that also considers the direction of motion of an object A. Which of the following is a scalar quantity? A.