SSC General Science: SSC, Railway and Other Examinations PDF
Preview SSC General Science: SSC, Railway and Other Examinations
General Science for SSC Examinations Railway Examinations CGL, Sub-Inspector in Delhi Police / Technical, Non-technical and CAPFs and Assistant Sub-Inspector in Group D Staff CISF, Junior Engineers, Stenographer C&D, CHSL (10+2), Multi Tasking (Non- Other State Examinations Technical) Staff and Others General Science for SSC Examinations Railway Examinations CGL, Sub-Inspector in Delhi Police / Technical, Non-technical and CAPFs and Assistant Sub-Inspector in Group D Staff CISF, Junior Engineers, Stenographer C&D, CHSL (10+2), Multi Tasking (Non- Other State Examinations Technical) Staff and Others Nitin Grewal McGraw Hill Education (India) Private Limited CHENNAI McGraw Hill Education Offices Chennai New York St Louis San Francisco Auckland Bogotá Caracas Kuala Lumpur Lisbon London Madrid Mexico City Milan Montreal San Juan Santiago Singapore Sydney Tokyo Toronto McGraw Hill Education (India) Private Limited Published by McGraw Hill Education (India) Private Limited, 444/1, Sri Ekambara Naicker Industrial Estate, Alapakkam, Porur, Chennai - 600 116 SSC General Science Copyright © 2018 by McGraw Hill Education (India) Private Limited No Part of this publication may be reproduced or distributed in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise or stored in a database or retrieval system without the prior written permission of the publishers. The program listings (if any) may be entered, stored and executed in a computer system, but they may not be reproduced for publication. This edition can be exported from India only by the publishers. McGraw Hill Education (India) Private Limited 1 2 3 4 5 6 7 8 9 D102542 22 21 20 19 18 Printed and bound in India ISBN (13) : 978-93-87572-86-7 ISBN (10) : 93-87572-86-2 Information contained in this work has been obtained by McGraw Hill Education (India), from sources believed to be reliable. However, neither McGraw Hill Education (India) nor its authors guarantee the accuracy or completeness of any information published herein, and neither McGraw Hill Education (India) nor its authors shall be responsible for any errors, omissions,or damages arising out of use of this information. This work is published with the understanding that McGraw Hill Education (India) and its authors are supplying information but are not attempting to render engineering or other professional services. If such services are required, the assistance of an appropriate professional should be sought. Typeset at Kaushik Laser Point & Printers, Tis Hazari Court, Delhi - 110 053 and printed at Sanat Printers, 312 EPIP, HSIDC, Kundli, Sonepat, Haryana Cover Design: Creative Designer Visit us at: www.mheducation.co.in Write to us at: [email protected] CIN: U22200TN1970PTC111531 Toll Free Number: 1800 103 5875 I dedicate this book to my parents, Sh. Dhup Singh and Late Smt. Santosh Devi P r e f a c e Before you dive deep There are many books on Science in market. But good quality books among them (like that of I. E. Irodov), are of high level, and their language is also very technical. Hence, for students preparing for one-day exams, such books remain useless, especially for those who never had science background in XI and XII class. In fact, those from science background too lack in core concepts many times. Then there are some GK books from famous publishers, which provide some help, but their content is so brief that it doesn’t help in exams much. They merge Geography, History, Science, Polity, Economy, etc., in the same book. But the way questions are framed in exams now-a-days, it tests your understanding of concept, for which mere cramming of facts won’t help. There is third type of books too, written by so-called “authors” for whom, grabbing money from book-market is prime concern, no matter even if the content quality is bad. Every other day, a new author rises with aspirations of getting a book printed to his or her name. When I roam around in Mukherjee Nagar, and randomly pick one of those books in book stores, I feel sad to see their texts full of mistakes. I have great hope with every new book. May be I get to learn something new out of them. But when the very first page I open, it shows signs of copy-paste, I hopelessly lose trust in rest of the content too. After all, students buy a book with a hope that it may help them in cracking exams, unaware of the mistakes in them. But such books are not only harmful to the aspirant in a competitive exam; they also do not do justice with a subject as royal as science. Eventually, students start hating science. What good does a copy-pasted book do if it depreciates the reputation of Science? Science isn’t that tough, as much it is usually portrayed, just that you need to keep applying logic while you go through a book (which every one of you can obviously do). And as far as physics is concerned, then besides being logical, this subject is also highly mathematical. Mathematics is the language of physics. You need to know basic mathematics to understand basic physics, and higher mathematics to understand higher physics. As a reader to comprehend this book, at least basic mathematical knowledge up to tenth class is expected from you. Apart from that, slight concepts of vector algebra and calculus will also be needed in some cases, which we will develop with the topic concerned. The purpose of this book is not to provide entertainment. You can’t go through it like a novel. According to a legend, Ptolemy-I-Soter, the king of Alexandria, who was studying geometry, asked Euclid if there was an easier way to understand it. Euclid said, “There are two types of roads in our country. Difficult ones, for common man, and royal roads for people like you. But there is just one way to geometry. There is no royal road to geometry”. I believe that the same applies to Physics too. No matter how hard I try to explain physics the easy way, unless you are ready to use your imagination, all my efforts would go in vain, especially when physics is so close to mathematics. There is no royal road to physics. So that you may get nice score in exams, here is my advice regarding this book. A few topics in this book are completely independent, and you can directly jump to those. But most of the other topics are interconnected. For example, if I were to teach about a pendulum, then I would need to explain gravity viii SSC General Science and centre of mass before that. This book is written in such an order so that every upcoming topic may be easier to understand. Do not jump on to those topics directly, from where you may have seen questions in previous years’ papers. Even if centre of mass is never asked in exams, you will still need to understand it to answer questions about pendulum. The flow of this book is more or less based on the NCERT books, starting from class XI. Hence, in case you feel the need to refer to a standard text, I would prefer the NCERT books because sequence of topics there will be somewhat similar to mine (except in some cases). However, I do not recommend studying the NCERT books directly, the reason being authors of the NCERT books have put a lot of content in little space. So, understanding the meaning of every word can be tricky with those books. Moreover, you will not find any numerical questions in most of your exams. Hence, I have tried to prepare such blend of standard texts along with my thoughts, which may benefit you the most. No one understands a concept for the first time. I still have many doubts about many topics. Hence, even if you have NOT already studied physics in your school days, don’t worry. If you know physics, read this book. If you don’t know physics, read it twice. I would like to express my heartfelt thanks to all those who have helped me write this book. Firstly, I’d like to thank all my teachers for they made me this able that I am capable of educating another generation further. I was highly motivated by my teachers Mr Narendra (Theta sir) and Mr Ravindra Panwar. I am thankful to my guide and friend, Arun Arora who inspired me to be an author. My students Aman Kumar, Tito and Latika have helped me type and translate the text. Also, my sisters Dr. Vijeta and Dr. Ritu have guided me all through my life, to strive forward, and aim for excellence. I am sincerely obliged to all of you. —Nitin Grewal
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