List of top Questions asked in WBJEE

Among the following groupings, which one represents the set of iso-electronic species?

The correct IUPAC name of $H_{3}C-C\left(CH_{3}\right)_{2} -CH =CH_{2}$ is

An n-p-n transistor of current gain 80 in common emitter mode gives emitter current equal to 8.1 mA. The base current is

The number of values of $k$ for which the equation $x^2 - 3x + k = 0$ has two distinct roots lying in the interval $(0, 1)$ are

The points of the ellipse $16x^2 + 9y^2 = 400$ at which the ordinate decreases at the same rate at which the abscissa increases is/are given by

A zener diode has break down voltage of 5.0 V. The resistance required to allow a current of 100 mA through the zener in reverse bias when connected to a battery of emf 12 V is

The number of points at which the function $f \left(x\right)=max \left\{a-x, a+x, b\right\}, -\infty, 0 < a < b$ cannot be differentiable

If $\frac{1}{^{5}C_{r}}+\frac{1}{^{6}C_{r}} =\frac{1}{^{4}C_{r}}$, then the value of $r$ equals to

The spin-only magnetic moment of $\left[crF_{6}\right]^{4-}$ (atomic number of Cr is 24) is

Which reaction is not appropriate for the synthesis of the following?

If $[x]$ denotes the greatest integer less than or equal to $x$, then the value of the integral $\int\limits^{{2}}_{{0}}x^2 [x] dx$

If the matrix $A=\begin{pmatrix}2&0&0\\ 0&2&0\\ 2&0&2\end{pmatrix},$ then $A^{n}=\begin{pmatrix}a&0&0\\ 0&a&0\\ b&0&a\end{pmatrix}, n\,\in\,N$ where

The letters of the word COCHIN are permuted and all permutation are arranged in an alphabetical order as in an English dictionary. The number of words that appear before the word COCHIN is

For non-zero vectors $\vec{a} $ and $\vec{b} $ if $\left|\vec{a}+\vec{b}\right|

The magnetic field intensity at the centre of cubical cage of identical wires of length ?a? due to a current I flowing as shown in the fiigure is

75% of a first order reaction was completed in 32 min. When would 50% of the reaction completed?

The emf of a Daniel cell at 298 K is $E_{1}.\qquad$The cell is $Zn | ZnSO_{4} \left(0.01M\right)|| CuSO_{4} \left(1M\right) | CU$ When the concentration of $ZnSO_{4}$ is changed to 1M and that of $CuSO_{4}$ to 0.01M, the emf changes to E2.The relationship between $E_{1} and E_{2}$ will be

Of the following atoms, which one has the highest n/p ratio?

General solution of $y \frac{dy}{dx}+by^{2}=a\,cos\,x, 0 < x< 1$ is

The value of cos $15^{\circ}\, cos 7 \frac{1^{\circ}}{2}\, sin 7 \frac{1^{\circ}}{2}$ is

In the complex ion $\left[Cu\left(CN\right)_{4}\right]^{3-}$ the hybridization state, oxidation state and number of unpaired electrons of copper are respectively

If the equation $x^2 + y^2 -10x + 21 = 0$ has real roots $x = a$ and $y=\beta$ then

The maximum number of 2p electrons with electronic spin $=-\frac{1}{2}$ are

Which of the following is the correct option for free expansion of an ideal gas under adiabatic condition?

For $N^{3-} >O^{2-}>F^{-} and Na^{+},$ the order in which their ionic radii varies is