Tuesday, June 17, 2014

A small note on Science subjects and strategy for Physics

Disclaimer: While aspirants might have come here reading the tag ‘Tips for Civil Services Examination’, I must candidly declare that there are actually no objective tips for this examination as such. I believe that every successful candidate has his/her own style of studying depending upon his/her background, strengths and weaknesses. However a proper guidance always helps and it is my endeavor in this blog to share my experiences and both what I did and what I think should be or should not be done.

Science optionals
Science optionals have been doing quite well for the past four to five years. While it can be often heard that optionals like Public Administration and Geography etc. are getting butchered, I think this may be more so because almost 50% of the candidates appearing in mains opt for these two optionals and hence the competition is immense. And UPSC is no longer accepting same clichéd answers picked up from class notes of famous coaching institutions. They are asking very innovative and currently relevant questions and expect expert answers. Moreover, I think a candidate with engineering or commerce background doesn’t have any edge when compared to someone who did graduation in Political Science or Public Administration etc. (of course I am talking about the majority and there may be exceptions). So if somebody is having really good foundation in science then Physics, Chemistry and Mathematics are good bets. The best thing about Science optionals is that once prepared well, one can be quite confident about solving the questions in exam and also estimate marks with decent precision. For example in the case of Physics, once whole syllabus is covered nicely, one can easily answer at least 80% (conservatively) of the paper very well and score minimum 50% (debatable) of the correct attempt.

A word of caution
There are two things however that one must be cautious of before opting for Science optional. 
First. One may find the syllabus extremely simple to look at or find some of the previous year questions very simple (of IIT-JEE or AIEEE level). For example there may be a simple question involving matrix in Mathematics, or one involving Young’s Double Slit in Physics. But one should rather not take impulsive decision based on this first impression and rather make a very informed choice. 
Second. Since Science optional, especially Physics and Mathematics, involve lots of derivations and formulae, it becomes very difficult to permanently memorize these and hence periodic revision is the only key to score well. If one is not able to revise Physics in the week before final examination, he/she may do very badly despite best preparation. In the current pattern mains examination is conducted in a period of five days in back to back fashion. So one must see if he/she has the ability to do that last moment revision swiftly (I will also be discussing how to manage it in this post).

I opted for Physics as my first optional because of strong interest and base in Physics. While I could also have opted for Electrical Engineering, but I found Engineering syllabus to be relatively vast. I took coaching from Vajpeyi Sir of DIAS in Delhi and was extremely satisfied. He covers the syllabus very nicely and one can even attempt the paper by only preparing from his class lectures (though I don’t suggest to limit oneself to class only). Only the topic of Electronics is not covered completely. Vajpeyi Sir’s style of teaching may not suit everyone (as he is very fast), but I found him to be an expert of Physics (for UPSC CSE) and his test series also helps in good evaluation before final exam. If one is regular in and after his class, I must say there can't be any guide better than Vajpeyi Sir for Physics. For me, he was also my first formal guide when I started my preparation, and ever since he has been a constant source of courage and motivation. The best thing about him is his candid way of telling you your weak points, which can help cementing the preparation. Not only for Physics, but he can also be approached for guidance in other areas i.e. GS, Essay or Interview.

One thing that must be borne in mind is that UPSC doesn’t want to test candidates’ proficiency in physics as it is not a recruitment exam for professor or scientist. UPSC wants to test how good an administrator one can be from the way he/she writes answers of Physics. So while being good in Physics is important, it is not the whole part of the story. Equally important is performance during those 3 hours for each paper in terms of quality, speed and choice of questions. Also only arriving at numerical results may not fetch good marks as in Physics writing all the relevant theory for each question asked is a must. Paper 2 is more theory based than Paper 1. At the same time one must not write unnecessary things to showcase knowledge as that may irritate the examiner. Usually examiners are highly experienced professors of Physics from reputed universities and they look for quality in answer as they know it and not some creative short-cut method. For every topic one studies for Physics, one must also prepare basic definitions (in own words) and while answering, use these definitions either in words or in equation form. Also if some particular phenomenon is being talked about, then explaining the underlying Physics in words is important than just writing simple mathematical solution. Diagrams where necessary must be neatly drawn.

Physics, as can be imagined, is very scientific subject and has to be approached scientifically. Currently each paper carries 250 marks with each question carrying 50 marks. This means each question has to be attempted in 35 minutes (7 minutes for 10 marks) whatsoever. This time limit is not at all difficult to stick to as one has to trim the answer according to the marks it carries. For example, a question may involve a slit diffraction numerical. Now if the question is asked for 10 marks only, then one can simply use the final result of diffraction pattern and apply formula after writing necessary theory. But if the same question is asked for 20 marks then the split diffraction pattern needs to be derived. Also the page length to be filled can be accordingly gauged depending upon one’s handwriting (for me it was around one page for 8 marks in 5 ½ minutes). Since space for answer is earmarked now, one can also take cue from the space allocated. But there is no need to fill all the space given as some write in very small font size.

In this subject each paper has 4 bits. If one thoroughly prepares three out of four, one can still comfortably attempt 90% of each paper, but that leaves you with no choice of questions and hence I recommend trying to complete whole syllabus. Also last bit on Solid state is in any case a bit difficult for not Electrical Engineering students and remains weak. So rest of the topics should be rock solid.

Making Notes

Making notes in one’s own handwriting is a very good way to learn Physics. During the whole preparation of Physics on has to go through a number of sources like coaching material, books, internet. These sources cannot be picked up every time one sits for revision and hence the notes come handy. Notes must also include some important difficult questions which can be quickly glanced at whenever possible. These notes also become important in current scenario when there may not be much gap during the mains exam for revision.


Solving all the questions of last 20 years Physics papers is the best and must way to practice. One can try writing answers as in exam conditions. Apart from that the last few years IFS (forest) exam papers can be solved if time allows.

Apart from the Vajpeyi Sir’s Class notes I used the following sources

Paper 1:

·         For most of the part Vajpeyi Sir’s notes are sufficient
·         The book by JC Upadhayay can be kept as reference book in general. It is good to give a thorough reading to this book (relevant topics) after reading class notes of DIAS. Central Force Motion, Angular Momentum, Rutherford Scattering, Rigid Body Mechanics and STR are covered well
·         Introduction to mechanics Kleppner -Kolenkow is another very good book that explains the basics very lucidly. Those who find STR difficult must read the chapters from this book
·         DC Mathur is good for solving practice questions and for mechanics of continuous media.
·         The book on Optics by Ajoy Ghatak is the Bible for this topic. It is a large book and one often may not find some topics (thanks to bizarre editing) very easily, but it actually has something or the other on every topic of this bit.
·         However optics is one topic where there is a lot of scope to write theory. Sometimes only theory based questions may also be asked. These questions have been dealt very nicely in a small book on Optics by BS Agarwal. I think it is a must to compliment the preparation with BS Agarwal.
     Electricity and Magnetism
·         This is one of the difficult topics (in my view) of Paper 1. Also there are many large derivations and lots of mathematics involved. But Introduction to Electrodynamics by D. J. Griffiths is a wonderful book for understanding the topics of Electrostatics and Magnetostatics. The book is one of the smoothest one may come across.
·         While Griffiths is a good book, but for this exam Electromagnetic Theory & Electrodynamics by Satya Prakash is more relevant. It extensively covers almost all topics of this chapter (except RLC circuits and Blackbody radiation) and has very good solved problems that often are asked in exam.
·         For Current electricity (RLC circuits) I did not do much (though I think I should not have ignored it so much as many questions were asked this year) as I have Electrical Engineering background.
·         Topics of BB radiation overlap with Thermal Physics and hence can be covered in books like Garg Bansal Ghosh or even HC Verma of Quantum Mechanics or Sears and Salinger
      Thermal and Statistical Physics
·         I covered this topic mostly from Vajpeyi Sir’s notes and then supplemented it with book by PK Chakrabarty. But this book is usually not considered the best source and I have heard that Garg Bansal Ghosh and Satya Prakash are better books.
·         For statistical physics theory part I did Sears and Salinger.
·         For Bose Einstein condensate derivation and Helium lambda curve, one can search internet as I did not find it in any book.

Paper 2: Resnick Eisberg is a reference book for first 3 topics of this paper. This I believe is a very scoring paper and is mostly theoretical in nature and hence making notes for this paper is even more important. In this paper one should try to write as much relevant theory as possible in every answer along with diagrams.
      Quantum Mechanics
·         Stick to HC Verma’s Quantum Physics (new edition) for this chapter and do it from cover to cover including all the solved and unsolved problems.
·         This book does not cover following topics very well: proof of Uncertainty principle and proof that minimum uncertainty occurs in Gaussian packet; Hydrogen atom full derivation, angular momentum derivation by solving differential equation. Uncertainty principle part can be searched on net and H atom and angular momentum are well covered in Resnick Eisberg
       Atomic and Molecular Physics
·         Atomic Physics: Book by Raj Kumar
·         Molecular Physics: Book by Banwell McCash
·         Reference book: Eisberg
       Nuclear Physics
·         This bit contains many small but important topics and should be covered well as almost all topics are asked with equal probability.
·         I did this part from varied sources. SB Patel is a good book to start with. But for theory part the book Resnick Eisberg has to be read (relevant chapters only) word by word.
·         I also referred to Brilliant Tutorial notes and Notes of Sh. Abhijeet Agarwal (AIR 24, 2010) (which can be found on his blog) for a sense of completion.
       Solid State and Electronics
·         Usually candidates do not cover this topic well because it is very complex in nature and not more than 30 marks compulsory will be asked from here.
·         But atleast solid state should be covered as it is not very difficult
·         One can refer to either SO Pillai (relevant chapter) or Raj Babbar (full book) for topics like superconductivity, crystal lattice, band theory, magnetic and thermal properties and specific heat of solids (which overlaps with Thermal Physics) and basics about semiconductors and npn pnp transistors and opamps. I recommend Raj Babbar because it is small and less frightening.
·         Logic gates, Karnaugh maps, Boolean algebra is also a very easy topic and can be covered from any good digital electronics book (Electrical/electronics students should not leave this)
·         One can skip the topic related to amplifiers and transistors as it may not be worth spending the time on.


  1. pls share your marks and strategy for GS and essay

  2. Hi, congrats for the sucess.
    Could you please answer this query+
    To show prezence of non centrl forces in the duetron structure. 2009, 20 mks.
    Would you explain that physically, or using msthematicl analysis as done in abhijeet agrawsl's notes?

    1. Since the question was asked for 20 marks in 2009, briefly mathematical solution should also be written if possible. But physical explanation is more important. You can write all details from various experimental values of properties like quadrupole moment etc to show both S and D configuration and conclude that since angular momentum is changing, there are non central nuclear forces. However, Usually this question will not be asked for more than 10 marks..

  3. Another question, when did you start prepaing for cse in gneral and phyics in particular?

    1. Though I completed my coaching for physics in 2010 june-september, i could not study for some time. I started rigorous preparation of GS and physics in August 2011 and attempted in 2012 and 2013.

  4. Hi Manish,
    Very informative piece of work for all the CSE aspiring candidates with Physics as Optional.
    I was wondering if you know someone (among your friends at DIAS) who cleared CSE with Chemistry as optional. I am planning to go for Chemistry as my optional.

    1. Sorry, Right now I don't know anyone with Chemistry optional personally. But I will try to connect you to some of them.

  5. congrats sir... do u have some tips for electrical engg. optional ?? how has been the result for this optional in CSE 2013??

    1. Hello gaurav
      Thanks. Electrical engg. is a very good and scoring optional. Usually very few candidates opt for it, because it being a specialised course. However if prepared well, it yields great results. In past Prakash Rajpurohit (AIR 2, CSE 2009) and Prince Dhawan (AIR 3, CSE 2011) have scored one of the highest scores. You can refer to http://princedhawan.wordpress.com/2012/06/21/strategy-for-electrical-engineering/ for strategy of Prince Dhawan.
      I will also try to get feedback of this year's candidates.

  6. congrats sir......can u please tell if the attempt in the physics mains paper is as per the guidelines given by Vajpayi sir & highlighted by u , what is the % of marks that can be obtained in the physics papers. what was ur total attempt & obtained % of marks

    1. Upto 60-65% of correct attempt can be obtained. I attempted around 225 in each paper.

  7. Hi Manish,

    I have just completed my MBA from IIMB and started working full time. Before that I have done my BTech in electrical engineering from IITK. Physics was and is one of my favorite subjects. I had a few questions:
    - In your opinion is it possible for a person to qualify Civil exam while working or is a break necessary?
    - In continuation of the above question, is it possible to prepare from the class notes of a good coaching insti without actually attending the classes?

    I have recently started seriously thinking about appearing for civil services exam and I hope I am not bothering you with some very basic questions.

    1. - One can appear and qualify while working simultaneously. People do that. But one has to manage time well
      -Attending coaching is not necessary. You can read notes and prepare.

    2. If you could provide a comprehensive list of few good sources for these notes(with physics as optional) it would be really helpful.

    3. I have already mentioned the topic wise books that you may be required to study. As far as notes are concerned Abhijeet Agrawal (AIR 24, CSE 2009) and Rishav Gupta (AIR 37, CSE 2013) have been kind enough to upload their handwritten notes from Vajpeyi Sir's class on their blogs. You will find them on Google.

  8. Sir, can you provide some tips on chemistry optional as well

  9. Hi sir, could you please tell how much space is provided in the answer sheet as per the marks? Did you have any trouble with it?
    Also, will you keep this blog active, just in case help is needed before the mains.

    1. space varies according to ques, but sufficient space is given..
      I cant promise, will try to remain active

  10. thanx for ur guidelines sir. sir, from where i can get previous year solved question papers?

  11. Sir, Are vajpayee sir's notes available in d market? I dnt think I will b able to attend his classes before 2014-15 mains due to paucity of time.

    1. You can ask for Shri Supreet Singh Gulati's (IAS) notes @ jawahar book depot, new delhi

  12. Sir, are vajpayee sir's class notes available in d market?

  13. Hello,

    I’ve taken up physics as my optional subject too and this would be my first attempt.I am a graduate in Electronics and have done my Masters in Applied Physics from IISc.
    I am working at Bangalore and considering there’s only ~3 months for the Mains exam need a few pointers from your side :
    1. How is one to improve answer writing. Could you kindly elaborate wrt UPSC Science(Physics) what is the expectation from the examiners POV?
    2. Apart from Electronics which is the most time consuming part in the syllabus. I ask this as I want to omit a topic other than electronics so i would be great full if you can tell me from your experience which is the best topic to skip? :)
    3.As i am at Bangalore can you suggest if you are aware of any correspondence course/test series that are available for physics prep. DIAS i enquired but apart from that i was unable to find any other institute.

    Hoping you’ll spare few minutes and reply.
    Thanks in advance.

    1. 1) if its a numerical, try to define various terms in the question. and then go on to solve the numerical/derivation. eg if the ques is about coriolis force, then you are expected to define it briefly, pref in words. FOr theory based question, you can directly go to the concept, or intuitively, also define various terms in between. add diagrams suitably
      2) electronics from paper 2 and EM from paper 1. Though i dont suggest you skip EM completely. atleast have some understanding of the topics involved. You may skip(at your own risk), TIR, dispersions etc.
      3) sorry, no idea

  14. Sir,can u tel which classes in Delhi are good to join for prelims n mains?
    plz plz me about optionals......................

  15. Sir,I have completed engg in ENTC this june.Is management a good choice for optional?or which optional do u think can be a good choice?

  16. sir,
    the abhijeet agarwar sir's link for the physics optional notes download has expired. is it possible for you to upload the same ?

    1. https://drive.google.com/folderview?id=0B0QY-7vDf3FXSnJ4YUpEZnBLazg&usp=sharing

  17. Sir, I am extremely confused about taking this optional, Can u guide me in this situation. As far as IIT is concerned I am for one of the IITS and why i want to choose this subject is this was one subject where i gave least input but got happy results. In IIT JEE also i gave least time to this subject but fetched me better marks.
    Secondly i have intrest in Psychology also, i have to choose between Psychology and Physics. These days Psychology is in great demand and there is high chance that after some time Psychology paper will be butchered.
    What subject to choose when i have no idea that how will i perform if i choose Psy. and there are lots of negative reviews about Physics.

  18. Sir,
    Thank you for the link.
    But sir can you upload the rest of the notes because i feel that relativity part is missing.
    Thanks again

  19. from where I got abhijeet aggarwal's notes for physics optional ...

  20. Sir...i m a hindi medium student and want to opt physics for CSE but most of seniors and teachers said that in hindi medium science subjects can not good marks fatching. so i confused .sir plz help me

  21. Hello Sir,
    I done my msc in physics but now I choosen Hindi medium and I want to opt physics. Is it possible if I take classes in English and try to write answers in Hindi( in physics). Please help me sir.

  22. Hello Sir,
    I done B.Sc(IT),and preparing for upsc physics as optional .Please help me sir.

  23. JEE Main 2019 answer key by Brilliant Pala Institute will be released on the day of the exam. Joint Entrance Examination main will be conducted by National Test Agency twice in a year.

  24. Does it possible to get good marks in physics without any coaching or guidance in cse

  25. Does it possible to get good marks in physics without any coaching or guidance in CSE..

  26. Sir, you mentioned that diagrams and charts etc. are helpful in physics.So sir, I request you to please give me an example and explanation about diagram and other things which make answer different from others.

  27. Sir,
    I am Pranav Khandal. I completed my graduation in computer science from manipal university jaipur. I am starting my preparation for CSE 2023 and thinking of opting physics as my optional. But sir my knowledge of physics is restricted to level of 10+2 only. I have always been fond of physics. I will be joining DIAS to start my physics preparation. But before that I want to know whether I can start classes at DIAS with physics knowledge of 10+2 level? Does Vajpayee Sir start his lectures with basics ? Will I be able to understand his lectures with my set of knowledge of physics of 10+2 level (as I do not have any knowledge of graduation level physics) ? Can Someone like me who has knowledge of physics of 10+2 level only join DIAS ? Or whether I must have some prerequisite knowledge of graduation level physics before I start my classes at DIAS?
    Plz guide sir I need your words of wisdom… Your guidance will help me in making my final call

  28. Sir , I am doing my BSC from Allahabad University and currently I am in 2nd year of college . Sir I also want to take physics as optional but I see the students from physics optional are from IIT background only so please help me sir that I should take physics as optional or not. Please help me sir