Hello warriors! Since the article on how sleep affects your performance was published on this site, some of NDA aspirants have reached out to me on FB complimenting and asking for tips to clear NDA exam. Since there are many tips and tricks on this site regarding the same, I’ll be showing the tips to make educated guesses to the questions you don’t have or have little idea about.
Let me make first thing very clear that, without practice and preparation, none can clear any exam; not even if he/she follows a vast array tips and tricks for the same. This article is for the people who studies very hard and gets confused over the choices of a question. It is recommended that you prepare well for the upcoming exams and try these while you take practice tests. I although do not guarantee the correct answer by these tips, but it’ll be far better than cramming, rolling pencils and peeking out in other’s papers. So, here we go:
1. Steer away from the Highest and the LowestÂ
In questions which have answers in numerical values, stay away from the extremes. In 60% cases, the highest and the lowest values are not the correct answers. Remember, only 60%, be careful in this!
2. Gamble on One of the Two Options
If you have already crossed out two incorrect answers, gamble on one of the two options in which you are confused. Use other tips here while choosing your pick such as the first one mentioned above.
3. No Negative Marking means You are in the Safe Zone
In case, there are questions like ‘Match the Following’ other similar questions which do not carry negative marking, you are free to play. Never leave such questions un-attempted. Study the marking scheme closely and also read the instructions given in the question paper carefully.
4. Easiest Topic that fetches you 30-40 Â Marks
Modern Physics with its atoms, nuclei, radiation and all cannot be just ignored. It fetches you as much 30-40 marks in entrance level exams and you hardly need more than a day or two to understand it all.
Just cram up all the formulae. You just can’t let these questions go. Strangely, it requires one-tenth of the preparation time you need for Mechanics but fetches you ten times the marks.
5. Units and Values
There are questions where they play on units and values in General Ability Test. Choose the unit mentioned in three options and choose the value that has been mentioned twice.
Let’s say, in a question related to Heat or Thermodynamics, the options are:
(a)Â Â Â 60 oK
(b)Â Â Â 70 oC
(c)Â Â Â 60 oC
(d)Â Â Â 50 oC
Now since three options mention degree Celsius, the chance of correct answer having oC in the unit part is 75%. Also see that the value 60 is mentioned in both Celsius and Kelvin. Hence, most probably it will be the right value.
Hence, we will choose (c) or 60 oC as our answer. This logic works in 80% of the cases!
6. Re-read Chapter 1 of Physics from your Class 11 NCERT Book
I wonder why no coaching institute pays much attention to this introductory chapter on Measurements. It is so easy and you get at least three questions from Dimensions, Approximation and finding Maximum Error sections.
Make sure you understand it clearly. Read the study material, go through the answer keys and check past year papers with solutions. It is easy and fetches you some ‘free’ marks.
7. Dimensional Analysis is your Friend in Crime
I wonder whether administrators put such questions only to mock students who actually solve them. Sometimes the options given as answers are just so laughable! Just the dimensional analysis of the weirdest questions will lead you to the correct answer – quickly and accurately.
Let’s say, there is a question in which you have to find velocity of an electromagnetic field with weird orientation. Its field values are given as B and E. The options are given as:
(a) (2E/B) 1/2
(b) (2B/E)
(c)Â (2E/B)
(d) (2B/E) 1/2
Now, you already know:
Dimensions of an Electric Field are (M1L1T-3A-1), and
Dimensions of a Magnetic Field are (M1L0T-2A-1).
Hence, only E/B gives you the Dimension of Velocity, which is (L1T-1). We do not need the square root as it will lead to the root of velocity too.
So, our answer is (c) in this case. You do not really need to check for ‘2E’ as only one option gives you correct dimensions.
8. NCERT for Chemistry
My teachers in Class XI and XII always used to say that NCERT books are the ‘Bible’ for all competitive entrance exams in India. And I, as usual, did not pay attention to what they said.
To my horror, I discovered what they said was so true!
So, here are my words of wisdom: Consider NCERT books as the books from where questions will be lifted from – directly. In Maths and Physics, there might be some questions from other books but in Chemistry – every question asked in IIT JEE and NDA was from the NCERT book the last year. In fact, in Inorganic Chemistry, some of the lines were directly quoted from the NCERT book – straight away Ctrl+C and Ctrl+V factor. 
9. Putting Values to Narrow Down your Options
Use this trick for questions in which you have to find general expressions for certain scenarios.
Let’s take an easy example. You have to find the expression for Pressure on a Bubble of Radius R in a container situated at H height from the ground level. The water in the container is up to height L.
Your options are:
(a)Â Â Â P + [pg (L-h)/LR]
(b)Â Â P + [pg LR/(L-h)]
(c)Â Â Â P + [pg R (L-h)/L]
(d)Â Â P + [pg (L-h)(L-R)/L)
The dimensional analysis will tell you that the first option is not correct. Similarly, the second option too gives you a dimension of Pressure per Unit Area and not just Pressure.
Now, we only have third and fourth options in hand.
We know that the Pressure on the surface of water must be P and (P + pg L) at the base of the container.
At the surface of water, h = L and Pressure = P. At the base of the container, h = 0 and Pressure = (P + pg L). Put these two values in the equations and you will find the correct answer – (d) in this case.
I’ll be updating more tips on making educated guesses in next article of the series-part 2 and will be focusing on mathematics. Do catch it up. Best Of luck!
