List of top Questions asked in JEE Main

Statement-I : \(\mathrm{KMnO_4}\) is a good reducing agent.
Statement-II : \(\mathrm{KMnO_4}\) reduces nitrite, oxalate and iodide ions.
$\text{C}_3\text{H}_6\text{Cl}_2$ (X) $\xrightarrow[\Delta]{\text{NaNH}_2 (2 \text{eq})}$ (Y) $\xrightarrow[\text{(ii) NaBH}_4]{\text{(i) Hg(OAc)}_2/\text{H}_2\text{O}}$ $\text{CH}_3\text{COCH}_3$. (Y) $\xrightarrow[\Delta]{\text{Fe/tube}}$ (Z).
Statement-I : Y gives yellow ppt. with $\text{NaOH}/\text{I}_2$.
Statement-II : Two types of H-atoms and one aromatic ring is present in Z and ratio of Z and X is 1 : 3.
Choose the correct option.
Observe the following reaction sequence: \[ (P) \xrightarrow[\Delta]{NH_3} (Q) \xrightarrow{Br_2/KOH} (R) \] Which of the following is the correct structure for \( P \), \( Q \) and \( R \)?
Consider the following reaction: \[ {Ca + 2HCl → CaCl2 + H2} \] If \(14\,\text{g}\) of calcium reacts with excess \( {HCl} \), choose the {incorrect} option.
Find the concentration of \( \text{X}^{2-} \) at equilibrium in 0.1 M \( \text{H}_2\text{X} \). Given \( K_{a1} = 2.5 \times 10^{-7} \) and \( K_{a2} = 1 \times 10^{-13} \).
In which of the following pairs first compound has more covalent nature than second compound? (a) \( \text{SnCl}_2, \text{SnCl}_4 \) (b) \( \text{PbCl}_4, \text{PbCl}_2 \) (c) \( \text{UF}_6, \text{UF}_4 \)
Consider the statements below: Statement I: BCl\(_3\) is covalent in nature. Statement II: BCl\(_3\) undergoes hydrolysis to form [B(OH)\(_4\)]\(^{+}\) and BH\(_2^{+}\). In the light of the above statements, choose the correct option.
A parallel plate capacitor with plate separation 5 mm is charged by a battery. On introducing a mica sheet of 2 mm while battery is connected, it is found that it draws 25% more charge. The dielectric constant of mica is :
For given nuclear reactions:
\[ ^4_2\mathrm{He} + ^1_0\mathrm{n} \rightarrow ^3_2\mathrm{He} + 20\,\text{MeV} \] \[ ^4_2\mathrm{He} + ^1_0\mathrm{n} \rightarrow ^4_2\mathrm{He} - 0.9\,\text{MeV} \] $X_3$ represents stability of $^3_2\mathrm{He}$, $X_4$ represents stability of $^4_2\mathrm{He}$ and $X_5$ represents stability of $^5_2\mathrm{He}$. Compare the stabilities.
Two discs have the same moment of inertia about their axes. Their thicknesses are \(t_1\) and \(t_2\) and they have the same density. If \( \dfrac{R_1}{R_2} = \dfrac{1}{2} \), then find \( \dfrac{t_1}{t_2} \).
Find \(A\) for dispersion without deviation.

Find magnetic field at midpoint O. Rings have radius $R$ and direction of current is in opposite sense. 

Detector \( D \) moves from \( A \) to \( B \) and observes the frequencies are differing by 10 Hz. The source is emitting frequency \( f_0 \) as shown: Speed of detector is 35 times less than speed of sound. Then \( f_0 \) is.
Two coherent loudspeakers \(L_1\) and \(L_2\) are placed at a separation of \(10\,\text{m}\) parallel to a wall at a distance of \(40\,\text{m}\) as shown in the figure. On a width \(AB\) on the wall, 10 maxima and minima are found. If the velocity of sound is \(324\,\text{m s}^{-1}\), find the frequency of sound. (Given: \( \sqrt{5}=2.23 \)).
A simple pendulum with a bob (mass \( m \) and charge \( q \)) is in equilibrium in the presence of a horizontal electric field \( E \). Then, the tension in the thread is \( F_1 \). Given \( \frac{F_1}{F_2} = \frac{2}{\sqrt{\alpha}} \), find \( \alpha \).
A ray parallel to the x-axis (principal axis of curved surface) is incident. The x-coordinate where the ray cuts the x-axis is: (The radius of curvature is 50 cm and \( \mu = 1.5 \)).
In a YDSE experiment, a transparent slab of refractive index 1.4 is placed in front of one slit. The fringe pattern shifts by 0.3 cm on the screen.
Given:
Screen distance = 60 cm
Slit separation = 1.5 mm
Thickness of the slab (in 碌m) is:
A cylindrical object of density $600\,\text{kg/m}^3$ and height $8$ cm is floating in a liquid of density $900\,\text{kg/m}^3$. Find height of cylinder inside liquid.
Which of the following cannot be measured:
For the given statements below, mark the correct option. Statement-I: Work done by a conservative force \( f \), from \( r_1 \) to \( r_2 \) is given by: \[ W = \int_{r_1}^{r_2} f \, dr. \] Statement-II: Work done by conservative force is path dependent.
An experiment is performed for comparing EMF of two cells using a potentiometer. For 1st cell, balancing length was achieved at 200 cm and for 2nd cell it was 150 cm. If least count of measurement of length of potentiometer wire is 1cm, the percentage error in the ratio of emf of two cells is :
Given that \[ \vec a=2\hat i+\hat j-\hat k,\quad \vec b=\hat i+\hat j,\quad \vec c=\vec a\times\vec b, \] \[ |\vec d\times\vec c|=3,\quad \vec d\cdot\vec c=\frac{\pi}{4},\quad |\vec a-\vec d|=\sqrt{11}, \] find $\vec a\cdot\vec d$.
Read the following statements:
(A) Q has more $\delta^-$ on chlorine than P.
(B) Q has more dipole moment than P.
(C) In Q, C–Cl bond has double bond character.
(D) In Q, Cl is attached to sp$^2$ hybridised carbon but in P, Cl is attached to sp$^3$.
(E) In Q, C–Cl bond length is more due to repulsion between lone pair on chlorine and $\pi$ electron in aromatic ring.
Let $z = (1+i)(1+2i)(1+3i)\cdots(1+ni)$ and $|z|^2 = 44200$. Find the value of $n$.
Hydroxy compound ($\text{A}$) with molecular mass $= 122$ react with excess of acetic anhydride and gives compound ($\text{X}$) with molecular mass $= 290$, then find the no. of hydroxy groups in given compound ($\text{A}$).