IIT JEE Physics (1978 to 2018: 41 Years) Topic-wise Complete Solutions

# Concepts of Physics: To The Students

..reproduced from the book Concepts of Physics.

Here is a brief discussion on the organisation of the book which will help you in using the book most effectively. The book contains 47 chapters divided in two volumes. Though I strongly believe in the underlying unity of physics, a broad division may be made in the book as follows:

• Chapters 1-14: Mechanics
• Chapters 15-17: Waves including wave optics
• Chapters 18-22: Optics
• Chapters 23-28: Heat and thermodynamics
• Chapters 29-40: Electric and magnetic phenomena
• Chapters 41-47: Modern Physics

Each chapter contains a description of the physical principles related to that chapter. It is well-supported by mathematical derivations of equations, descriptions of laboratory experiments, historical background etc. There are "in-text" solved examples. These examples explain the equation just derived or the concept just discussed. These will help you in fixing the ideas firmly in your mind. Your teachers may use these in-text examples in the class-room to encourage students to participate in discussion.

After the theory section, there is a section on Worked Out Examples . These numerical examples correspond to various thinking levels and often use several concepts introduced in that chapter or even in previous chapters. You should read the statement of a problem and try to solve it yourself. In case of difficulty, look at the solution given in the book. Even if you solve the problem successfully, you should look into the solution to compare it with your method of solution. You might have thought of better method, but knowing more than one method is always beneficial.

Then comes the part which tests your understanding as well as develop it further. Questions for short Answer generally touch very minute points of understanding. It is not necessary that you answer these questions in a single sitting. They have great potential to initiate very fruitful discussions. So, freely discuss these questions with your friends and see if they agree with your answer. Answers to these questions are not given for the simple reason that the answers could have cut down the span of such discussions and that would have sharply reduced the utility of these questions.

There are two sections on multiple choice questions namely OBJECTIVE I and OBJECTIVE II. There are four options following each of these questions. Only one option is correct for OBJECTIVE I questions. Any number of options, zero to four, may be correct for OBJECTIVE II questions. Answers to all these questions are provided.

Finally, a set of numerical problems are given for your practice. Answers to all these problems are also provided. The problems are generally arranged according to the sequence of the concepts developed in the chapter but they are not grouped under section-headings. I don't want to bias your ideas beforehand by telling you that this problem belongs to that section and hence use that particular equation. You should yourself look into the problem and decide which equations or which methods should be used to solve it. Many of the problems use several concepts developed in different sections of the chapter. Many of them even use the concepts from the previous chapters. Hence, you have to plan out the strategy after understanding the problem.

Remember, no problem is difficult. Once you understand the theory, each problem will become easy. So, don't jump to exercise problems before you have gone through the theory, the worked out problems and the objectives. Once you feel confident in theory, do the exercise problems. The exercise problems are so arranged that they gradually require more thinking.

I hope you will enjoy Concepts of Physics.

H. C. Verma