List of top Questions asked in WBJEE

Consider the following diagram and mark the correct answer.

If $A=\left(\begin{array}{cc}3& x-1\\ 2x+3& x+2\end{array}\right)$ is a symmetric matrix, then the value of $x$ is

Directions: The following question has four choices, out of which one or more are correct.When photons of energy 4.25 eV strike the surface of a metal $A$, the ejected photoelectrons have minimum kinetic energy $T_A$ expressed in eV and de Broglie wavelength ${\lambda }_A.$ The maximum kinetic energy ofphotoelectrons liberated from another metal $B$ by photons of energy 4.70 eV is $T_B=(T_A-1.50eV)$. If the de Broglie wavelength of these photoelectrons is ${\lambda }_B=2{\lambda }_A$, then

If $\omega (\ne 1)$ is a cube root of unity and ${(1+{\omega }^2)}^n={(1+{\omega }^4)}^n,$ then the leastpositive value of $n$ is

0.400 g of impure CaSO4 (Molar mass = 136) solution when treated with excess of barium chloride solution, gave 0.617 g of anhydrous BaSO4 (Molar mass = 233). The percentage of CaSO4 present in the sample is

0.066 g of a metal was deposited when a current of 2 ampere passed for 100 seconds through an aqueous solution of its metal ion. The equivalent mass of the metal is-

The following reaction is an example of

A galvanometer has 40 divisions and a sensitivity of 12 μA/div. it can be converted into a voltmeter to read 3 V by connecting-

An integrating factor of the differential equation $x\frac{dy}{dx}+y\log x=x{e}^x{x}^{-\frac{1}{2}\log x},(x>0)$

ABCD is a parallelogram. If $P$ and $Q$ are the respective midpoints of$\overrightarrow{\mathrm{BC}}$ and $\overrightarrow{\mathrm{AD}},$ then $,\overrightarrow{\mathrm{AB}}+\overrightarrow{\mathrm{DC}}$ is equal to

The value of $\sec [{\tan }^{-1}\left(\frac{b+a}{b-a}\right)-{\tan }^{-1}\left(\frac{a}{b}\right)]$

The energy of electron in 1st orbit of Hydrogen atom is –2.18 × 10^-18 Joule. The third ionisation energy of Li⁺² ion is

In $P{O}_4^{3-}$the formal charge on each oxygen atom and P − O bond order respectively are

The minimum value of $f(x)={\sin }^{4}x+{\cos }^{4}x,0\le x\le \frac{\pi }{2}$

The probability that in a family of 5 members, exactly 2 members have birthdays on Sunday, is

If A1, A2; G1, G2; and H1, H2 are two AMs, GMs and HMs between two quantities, then the value of $\frac{G_1{G}_2}{H_1{H}_2}$ is

If $\overrightarrow{A}=\hat{i}+2\overrightarrow{j}+3\hat{k},\overrightarrow{B}=-\hat{i}+2\hat{j}+\hat{k},\overrightarrow{C}=3\hat{i}+j$ and $\overrightarrow{A}+1\overrightarrow{B}$ is perpendicular to $\overrightarrow{\mathrm{C}},$ thent is equal to

An electron jumps from the fourth orbit to the second orbit of hydrogen atom. If Rydberg’s constant R is equal to 10⁷ m^–1, then the frequency of the emitted radiation in Hz will be

If a particle moves in such a way that the displacement is proportional to the square of the velocity acquired, then its acceleration is

Consider the reaction 2A + B →products, when the concentration of A alone was doubled, the half-life of the reaction did not change. When the concentration of B alone was doubled, the rate was not altered. The unit of rate constant for this reaction is

Which of the following type of compound is used to increase the hardness of the silicone polymer.

The curve represented by the equation 4x² + 16y² - 24x - 32y - 12 = 0 is

The derivative of${\tan }^{-1}\left(\frac{\sqrt{1+x^2}-1}{x}\right)$ with respect to ${\tan }^{-1}\left(\frac{2x\sqrt{1-x^2}}{1-2x^2}\right)$ at $x=0$

The actinoids exhibit more number of oxidation states in general than the lanthanoids because

The solubility product of silver chloride is 1.8 × 10^-10 at 298 k. The solubility of AgCl in 0.01 M KCl aqueous solution in mol dm^-3 is