List of top Questions asked in JEE Main

The density of $3M$ solution of sodium chloride is $1.252\, g\, mL^{-1}$. The molality of the solution will be: (molar mass, $NaCl = 585\, g\, mol^{-1}$)

A mass of $50\,g$ of water in a closed vessel, with surroundings at a constant temperature takes $2$ minutes to cool from $30^\circ C$ to $25^\circ C$. A mass of $100\,g$ of another liquid in an identical vessel with identical surroundings takes the same time to cool from $30^\circ C$ to $25^\circ C$. The specific heat of the liquid is: (The water equivalent of the vessel is $30\,g$.)

\(500 \,g\) of water and \(100\, g\) of ice at \(0^{\circ}C\) are in a calorimeter whose water equivalent is \(40\, g\). \(10\, g\) of steam at \(100^\circ C\) is added to it. Then water in the calorimeter is : (Latent heat of ice \(= 80\, cal/g\), Latent heat of steam \(=540\, cal/g\))

In Goldschmidt aluminothermic process which of the following reducing agents is used:

Copper crystallises in fcc with a unit length of $361\,pm$. What is the radius of copper atom ?

In which of the following pairs of molecules/ions both the species are not likely to exist?

In a face centred cubic lattice, atoms of $A$ form the comer points and atoms of $B$ form the face centred points. If two atoms of $A$ are missing from the comer points, the formula of the ionic compound is :

The first ionisation potential of $Na$ is $5.1\, eV$. The value of electron gain enthalpy of $Na^+$ will be

Vapour pressure of pure benzene is $119$ torr and that of toluene is $37.0$ torr at the same temperature. Mole fraction of toluene in vapour phase which is in equilibrium with a solution of benzene and toluene having a mole fraction of toluene $0.50$, will be :

Let $x_1 , x_2,...., x_n$ be n observations, and let $\bar{x}$ be their arithmetic mean and $\sigma^2$ be the variance. Variance of $2x_1, 2x_2, ..., 2x_n$ is $4 \sigma^2$. Arithmetic mean $2x_1, 2x_2, ..., 2x_n $ is 4 $\bar{x}$ .

Let R be the set of real numbers A = {(x, y) $\in$ R $\times$ R : y - x is an integer} is an equivalence relation on R. B = {(x, y) $\in$ R $\times$ R : x = $\alpha$y for some rational number $\alpha$} is an equivalence relation on R.

If $ {{\cos }^{-1}}\left( \frac{5}{13} \right)-{{\sin }^{-1}}\left( \frac{12}{13} \right)={{\cos }^{-1}}x, $ then $ x $ is equal to

The variance of first n even natural numbers is $\frac{n^2 - 1}{4}$. The sum of first n natural numbers is $\frac{n(n + 1)}{2}$ and the sum of squares of first n natural numbers is $\frac{n(n + 1)(2n +1)}{6}$.

Which of the following statements is true?

An artificial radioactive isotope gave ${^{14}_{7}N}$ after two successive $\beta$ -particle emissions. The number of neutrons in the parent nucleus must be :

The vector sum of two forces is perpendicular to their vector differences. In that case the forces

Probability of four sons to a couple is

The potential difference applied to an X-ray tube is increased. As a result, in the emitted radiation

Number of ambidentate nucleophiles among the following is:
CN^-, SCN^- NO₂^-, CH₃COO^-, C₂0₄^2-, NH₂^-, SO₄^2-

Five identical convex lenses are placed one after the other in close contact. The power of this arrangement is 25 D. Then, the power of one such lens is

A cubical arrangement of 12 resistors each having resistance R is shown. Find I.

On a given rough incline plane, a solid sphere and a hollow cylinder having the same radius are rolled one by one, with the same speed. Ratio of heights attained by solid sphere and hollow cylinder is

A wooden block is initially at rest on a smooth surface. Now a horizontal force is applied on the block which increases linearly with time. The acceleration- time (a - t) graph for the block would be

Which graph correctly represents the photo current (i) vs stopping potential (Vs) for the same frequency but different intensity? $(here, I_1 › I_2)$

An electron is projected along the axis of solenoid which carries constant current i, the trajectory of electron shall be