List of top Questions asked in WBJEE

A hemisphere of radius $R$ is placed in a uniform electric field $E$ so that its axis is parallel to the field. Which of the following statement(s) is/are true?
hemisphere of radius R is placed in a uniform electric field
In Bohr's model of the atom, the radius of a hydrogen atom in the ground state is $r_1$ and the radius of a He+ ion in the ground state is $r_2$. Which of the following is correct?
During the preparation of NH3 in Haber’s process, the promoter(s) used is/are:
If the kinetic energies of an electron, an alpha particle, and a proton having the same de-Broglie wavelength are $\varepsilon_1, \varepsilon_2, \varepsilon_3$ respectively, then
XeF2, NO2, HCN, ClO2, CO2 Identify the non-linear molecule-pair from the above mentioned molecules.
Avogadro's law is valid for
The number of unpaired electrons in $Mn^{2+}$ ion is
The number of atoms in body-centred and face-centred cubic unit cell respectively are
The correct pair of electron affinity order is:
Sodium nitroprusside is:
Oxidation states of Cr in K2Cr2O7 and CrO5 are, respectively:
In a Young's double slit experiment, the intensity of light at a point on the screen where the path difference between the interfering waves is $\lambda$ (where $\lambda$ is the wavelength of light used) is $1$. The intensity at a point where the path difference is $\frac{\lambda}{4}$ will be (assume two waves have the same amplitude)
The metal-pair that can produce nascent hydrogen in alkaline medium is:
An electron revolves around the nucleus in a circular path with angular momentum $L$. A uniform magnetic field $B$ is applied perpendicular to the plane of its orbit. If the electron experiences a torque $T$, then
A straight wire is placed in a magnetic field that varies with distance $x$ from origin as $B = B_0 (2 - \frac{x}{n}) \hat{k}$. The ends of the wire are at $(a, 0)$ and $(2n, 0)$ and it carries a current $I$. If the force on the wire is $F = 1 B_0 \left(\frac{k a}{2}\right) \hat{j}$, then the value of $k$ is
Pick the correct statement:
When an AC source of EMF $E$ with frequency = 100 Hz is connected across a circuit, the phase difference between $E$ and current $I$ in the circuit is observed to be $\pi/4$ as shown in the figure. If the circuit consists of only RC or RL in series, then
When an AC source of EMF
Two charges, each equal to $-q$, are kept at $(-a, 0)$ and $(a, 0)$. A charge $q$ is placed at the origin. If $q$ is a small displacement along the $y$ direction, the force acting on $q$ is proportional to
A sample of MgCO3 is dissolved in dilute HCl and the solution is neutralized with ammonia and buffered with NH4Cl / NH4OH. Disodium hydrogen phosphate reagent is added to the resulting solution. A white precipitate is formed. What is the formula of the precipitate?
The correct order of acidity of the following hydra acids is:
Hybridisation of the negative carbons in (1) and (2) are:
Hybridisation of the negative carbons
The correct statement(s) about B2H6 is/are:
The human eye has an approximate angular resolution of $\theta = 5.8 \times 10^{-4}$ rad, and a typical photo printer prints a minimum of 300 dpi (dots per inch, $1$ inch = $2.54$ cm). At what minimal distance $d$ should the printed page be held so that one does not see the individual dots?
A body of mass $m$ is thrown with velocity $u$ from the origin of a coordinate axes at an angle with the horizon. The magnitude of the angular momentum of the particle about the origin at time $t$ when it is at the maximum height of the trajectory is proportional to
Which of the following is radioactive?