List of top Questions asked in JEE Main

The increasing order of diazotisation of the following compounds is :

In the leaching method, bauxite ore is digested with a concentrated solution of NaOH that produces ?X?. When $CO_2$ gas is passed through the aqueous solution of ?X?, a hydrated compound ?Y? is precipitated. ?X? and ?Y? respectively are :

Consider the following two statements : The value of $\sin \, 120^{\circ}$ can be derived by taking $\theta =240^{\circ}$ in the equation $2 \sin \, \frac{\theta}{2} = \sqrt{1 + \sin \, \theta} - \sqrt{1 - \sin \, \theta}$. The angles A, B, C and D of any quadrilateral ABCD satisfy the equation $\cos \left( \frac{1}{2} (A + C) \right) + \cos \left( \frac{1}{2} (B + D) \right) = 0 $ Then the truth values of p and q are respectively :

Which of the following statements is false?

The value closest to the thermal velocity of a Helium atom at room temperature $(300\, K)$ in $ms^{-1}$ is :$ [k_B = 1.4 \times 10^{-23} \, J/K; m_{He} = 7 \times 10^{-27} \, kg ]$

A power transmission line feeds input power at $2300\, V$ to a step down transformer with its primary windings having $4000$ turns, giving the output power at $230\, V$. If the current in the primary of the transformer is $5\, A$, and its efficiency is $90\%$, the output current would be :

In a screw gauge, $5$ complete rotations of the screw cause it to move a linear distance of $0.25\, cm$. There are $100$ circular scale divisions. The thickness of a wire measured by this screw gauge gives a reading of $4$ main scale divisions and $30$ circular scale divisions. Assuming negligible zero error, the thickness of the wire is :

When metal ? $M$ ? is treated with $NaOH$, a white gelatinous precipitate ?$X$? is obtained, which is soluble in excess of $NaOH$. Compound ?$X$? when heated strongly gives an oxide which is used in chromatography as an adsorbent. The metal ?$M$? is :

If the length of the latus rectum of an ellipse is $4$ units and the distance between a focus and its nearest vertex on the major axis is $\frac{3}{2}$ units, then its eccentricity is :

Which of the following arrangements shows the schematic alignment of magnetic moments of antiferromagnetic substance ?

A group 13 element 'X' reacts with chlorine gas to produce a compound $XCl _{3} . XCl _{3}$ is electron deficient and easily reacts with $NH _{3}$ to form $Cl _{3} X \leftarrow NH _{3}$ adduct; however, $XCl _{3}$ does not dimerise. $X$ is

Which graph corresponds to an object moving with a constant negative acceleration and a positive velocity ?

In an experiment a sphere of aluminium of mass 0.20 kg is heated upto $150^{\circ}C$. Immediately, it is put into water of volume 150 cc at $27^{\circ}C$ kept in a calorimeter of water equivalent to 0.025 kg. Final temperature of the system is $40^{\circ}C$. The specific heat of aluminium is : (take 4.2 Joule=1 calorie)

1 gram of a carbonate $(M_2CO_3)$ on treatment with excess $HCl$ produces $0.01186$ mole of $CO_2$. The molar mass of $M_2CO_3$ in g $mol^{-1}$ is :

Excess of $NaOH_{(aq)}$ was added to $100\, mL$ of ${ FeCl_3}$ (aq) resulting into $2.14\, g$ of ${Fe(OH)_3}$. The molarity of ${FeCl_3}$ (aq) is : (Given molar mass of ${Fe = 56 \, g \, mol^{-1}}$ and molar mass of ${Cl = 35.5 \, g \, mol^{-1}}$)

A time dependent force $F = 6t$ acts on a particle of mass $1\,kg$. If the particle starts from rest, the work done by the force during the first $1\,sec$. will be :

Let $l_n = \int \tan^{n} x \, dx , (n > 1) . l_4 + l_6 = a \, \, \tan^5 \, x + bx^5 + C$, where $C$ is a constant of integration, then the ordered pair $(a, b)$ is equal to :

An observer is moving with half the speed of light towards a stationary microwave source emitting waves at frequency $10\, GHz$. What is the frequency of the microwave measured by the observer ? (speed of light $= 3 \times 10^8 \, ms^{-1}$)

When a current of $5 \,mA$ is passed through a galvanometer having a coil of resistance $15 \, \Omega$, it shows full scale deflection. The value of the resistance to be put in series with the galvanometer to convert it into a voltmeter of range $0-10 \,V$ is :

A slender uniform rod of mass $M$ and length $l$ is pivoted at one end so that it can rotate in a vertical plane (see figure). There is negligible friction at the pivot. The free end is held vertically above the pivot and then released. The angular acceleration of the rod when it makes an angle $\theta$ with the vertical is :

An external pressure \(P\) is applied on a cube at \(0^{\circ}C\) so that it is equally compressed from all sides.\(K\) is the bulk modulus of the material of the cube and \(\alpha\) is its coefficient of linear expansion.Suppose we want to bring the cube to its original size by heating it. The temperature should be raised by :

The integral $\int\limits^{\frac{3\, \pi}{4}}_{\frac{\pi}{4}} \frac{dx}{ 1 + \cos \, x}$ is equal to :

The rate of a reaction quadruples when the temperature changes from $300$ to $310\, K$. The activation energy of this reaction is : (Assume activation energy and pre-exponential factor are independent of temperature; $ln\, 2 = 0.693; R=8.314 \,J$ $mol^{-1} \, K^{-1}$)

For a reaction, $ {A_(g) \to A_(l); \Delta H = - 3RT}$. The correct statement for the reaction is :