Most Repeated Questions in JEE Mains: Comprehensive Analysis

Most repeated questions in JEE Main Physics

In JEE Mains, Physics questions often come from a few important topics that are repeated every year. Understanding these topics can give you an idea about what topics you should prepare and, more importantly, what you should not waste your time on. Given below is a list of the most repeated Physics questions that you should be practising and preparing for the JEE Main 2027 Syllabus:

Some of the JEE Main questions of Physics based on most repeated concepts and patterns are given below. Students can also refer to the JEE Main 2027 Sample Paper:

Question: A plane electromagnetic wave propagates along the +x direction in free space. The components of the electric field, E→ and magnetic field, B→, vectors associated with the wave in the Cartesian frame are :

(1) Ey, Bx

(2) Ey, Bz

(3) Ex, By

(4) Ez, By

Solution:

Direction of propagation $= \vec{E} \times \vec{B}$

$\vec{E} \to y, \quad \vec{B} \to z, \quad \vec{c} \to x$

$\hat{E} \times \hat{B} = \hat{j} \times \hat{k} = \hat{i} = \hat{c}$

Hence, the answer is option (2).

Question: Given below are two statements :

Statement I: For transmitting a signal, the size of the antenna (I) should be comparable to the wavelength of the signal (at least l=λ4 in dimension)

Statement II: In amplitude modulation, the amplitude of the carrier wave remains constant (unchanged).

In light of the above statements, choose the most appropriate answer from the options given below.

(1) Statement I is correct, but Statement II is incorrect

(2) Both Statement I and Statement II are correct

(3) Statement I is incorrect, but Statement II is correct

(4) Both Statement I and Statement II are incorrect

Solution:

Statement 1 is correct.

In modulation, the amplitude of the carrier wave is increased.

Statement 2 is incorrect; in amplitude modulation, the amplitude of the wave is varied.

Hence, the answer is option (1).

Most repeated questions in JEE Main Chemistry

Chemistry includes conceptual as well as numerical questions. Among the most repeated questions in JEE Mains Chemistry, Organic and Physical Chemistry dominate. Practising questions from frequently asked Chemistry topics can significantly improve accuracy and scoring potential. A few questions are given in the table below. Download the free PDF.

Also check: JEE Main Inorganic Chemistry: Complete Exceptions Handbook with Practice Questions (2027 Edition)

Some of the questions based on most repeated topics in JEE Main Chemistry are given below:

Question: Concentrated nitric acid is labelled as 75% by mass. The volume in mL of the solution which contains 30 g of nitric acid is __ . Given: Density of nitric acid solution is 1.25 g/mL

(1) 45

(2) 55

(3) 32

(4) 40

Solution:

75% by mass means: $\because 75\ g\ HNO_3$ in $100\ g$ solution.

$\therefore 30\ g\ HNO_3$ in $\dfrac{100}{75} \times 30\ g$ solution.

$m_{solution} = \dfrac{100 \times 30}{75}\ g$

$\because V_{sol} = \dfrac{m_{sol}}{d_{sol}} = \dfrac{100 \times 30}{75 \times 1.25} = 32\ mL$

Hence, the correct answer is option (3).

Question: Given below are two statements :

Statement I: $\mathrm{CrO}_3$ is a stronger oxidising agent than $\mathrm{MoO}_3$

Statement II : Cr(VI) is more stable than Mo(VI)

In light of the above statements, choose the correct answer from the options given below

(1) Statement I is false, but Statement II is true

(2) Statement I is true, but Statement II is false

(3) Both Statement I and Statement II are true

(4) Both Statement I and Statement II are false

Solution:

Statement I: $CrO_3$ is indeed a stronger oxidising agent than $MoO_3$.

Here, $Cr^{6+}$ is less stable than $Mo^{6+}$ as $CrO3$ tends to get reduce to $Cr^{3+}$ more easily than $Mo^{6+}$ to $Mo^{3+}$. Hence, $CrO3$ is a stronger oxidising agent. Statement I is TRUE.

Statement II: $Cr(VI)$ is more stable than $Mo(VI)$.

It is not correct as the order of stability of the oxidation states of group 6 elements is:

$Cr^{6+} < Mo^{6+}$

The order is that Mo(VI) is more stable, as in group oxidation states, stability increases in the downward direction. Statement II is FALSE.

Thus, Statement II is not correct. Thus, Statement I is true, Statement II is false.

Option (2) is the correct answer.

Most repeated questions in JEE Main Maths

Mathematics questions often involve direct applications of formulas and standard problem-solving techniques. Here are the JEE Main questions with the most repeated concepts of Maths. The most asked questions in JEE Mains of maths are predominantly involved in important formulas and standard techniques, making them critical for scoring well. There are a few topics where more questions are asked, as follows.

Here are some of the important questions from JEE Main Mathematics.

Question: If in the expansion of

$
(1+x)^p(1-x)^q
$

the coefficients of $x$ and $x^2$ are 1 and -2 respectively, then $p^2+q^2$ is equal to
1. 8
2. 18
3. 13
4. 1

Solution:

Using the binomial expansion,

$
(1+x)^p=1+p x+\binom{p}{2} x^2+\cdots
$$

and

$
(1-x)^q=1-q x+\binom{q}{2} x^2+\cdots
$

Multiplying,

$
(1+x)^p(1-x)^q=\left(1+p x+\binom{p}{2} x^2+\cdots\right)\left(1-q x+\binom{q}{2} x^2+\cdots\right)
$

Coefficient of $x$

$
p-q=1 .
$

Hence,

$
p=q+1 .
$

Coefficient of $x^2$

$
\binom{p}{2}+\binom{q}{2}-p q=-2 .
$

Substituting $p=q+1$,

$
\frac{(q+1) q}{2}+\frac{q(q-1)}{2}-q(q+1)=-2 .
$

Simplifying,

$
\begin{gathered}
q^2-q^2-q=-2, \\
-q=-2, \\
q=2 .
\end{gathered}
$

Therefore,

$
p=q+1=3 .
$

Now,

$
p^2+q^2=3^2+2^2=9+4=13 .
$

Option 3 is correct.

Question: If

$
I=\int_{0}^{\pi/4}\cos 2x\,\sin 2x\,(\cos 3x+\sin 3x)^2\,dx,
$

then $I$ is equal to:

(1) $\frac{1}{12}$
(2) $\frac{1}{9}$
(3) $\frac{1}{6}$
(4) $\frac{1}{3}$

Solution:

$
I=\int_0^{\pi / 4} \cos 2 x \sin 2 x(\cos 3 x+\sin 3 x)^2 d x
$

Since

$
(\cos \theta+\sin \theta)^2=\cos ^2 \theta+\sin ^2 \theta+2 \sin \theta \cos \theta=1+\sin 2 \theta,
$

we have

$
(\cos 3 x+\sin 3 x)^2=1+\sin 6 x .
$

Also,

$
\sin 6 x=2 \sin 3 x \cos 3 x
$

and

$
1+\sin 6 x=(\sin 3 x+\cos 3 x)^2 .
$

Using

$
\cos 2 x \sin 2 x=\tan 2 x \sec ^{-2} 2 x,
$

the integral can be written as

$
I=\int_0^{\pi / 4} \tan 2 x \sec ^2 2 x(1+\tan 3 x)^2 d x
$

Let

$
t=1+\tan 3 x .
$

Then

$
\frac{d t}{d x}=3 \sec ^2 3 x=3\left(1+\tan ^2 3 x\right) .
$

Using the given substitution form,

$
3 \tan 2 x \sec ^2 2 x d x=d t,
$

or

$
\tan 2 x \sec ^2 2 x d x=\frac{d t}{3} .
$

When

$
\begin{gathered}
x=0 \\
t=1+\tan 3(0)=1
\end{gathered}
$

When

$
\begin{gathered}
x=\frac{\pi}{4}, \\
t=1+\tan \left(\frac{3 \pi}{4}\right)=1+(-1)=0 .
\end{gathered}
$

Therefore,

$
\begin{gathered}
I=\frac{1}{3} \int_1^2 \frac{d t}{t^2} \\
I=\frac{1}{3}\left[-\frac{1}{t}\right]_1^2 \\
I=\frac{1}{3}\left[-\frac{1}{2}-\left(-\frac{1}{1}\right)\right] \\
I=\frac{1}{3}\left[-\frac{1}{2}+1\right] \\
I=\frac{1}{3}\left[\frac{1}{2}\right] \\
I=\frac{1}{6}
\end{gathered}
$

Option 3 is correct.

Also check: JEE Main 2027 Study Guide Complete Notes, Important Concepts, Formulae and Practice Questions

Why Focus on Repeated Questions?

If a candidate focuses on the questions from most repeated topics for JEE Mains physics, chemistry and maths, his/her chances of achieving a better score can significantly increase. High Chance of Appearance: Certain topics/chapters appear every year in each of the three subjects. Some popular topics include: Physics- electrostatics, modern physics, mechanics (in terms of specific questions), etc. Chemistry- chemical bonding, coordination compounds, organic reactions (all the named reactions and mechanisms), etc.

Time efficiency: The candidate can solve the questions much faster when it's a repeated question. This will also increase the speed and accuracy. Attempting all known questions first will definitely earn you the much-needed marks and leave you with enough time to think about the other questions.

Pattern recognition of questions: Knowing the repetitive questions, you can recognise the patterns of the question and exam trends, like how a certain question of a particular topic is presented in multiple-choice question form, and what the common tricks are to solve numerical problems related to certain concepts. Knowing the pattern, you will never make mistakes, and you will also be more confident during the exam.

Effective Revision strategy: Practising repetitive questions, you will have more opportunities to revise certain topics effectively. You will no longer need to focus on each of the topics equally, but on high-yield topics which have been appearing in the examination, and this strategy will also help you to memorise formulas, concepts, and shortcuts effectively.

Boost of confidence and stress reduction: By solving repeated questions, you naturally become more confident because you already know how to attempt the specific questions which are going to appear in the exam. This, in turn, reduces the stress of the examination and helps to maintain a calm and cool head on the examination day.

Also Read:

JEE Main Important Formulas PDF

JEE Main 2027 Chapter Wise Weightage