List of top Questions asked in WBJEE

A neutral conducting solid sphere of radius $R$ has two spherical cavities of radii $a$ and $b$ as shown in the figure. The center-to-center distance between the two cavities is $c$. $q_a$ and $q_b$ charges are placed at the centers of cavities respectively. The force between $q_a$ and $q_b$ is
A neutral conducting solid sphere of radius
A particle is subjected to two simple harmonic motions in the same direction having equal amplitudes and equal frequency. If the resultant amplitude is equal to the amplitude of the individual motion, the phase difference $(\delta)$ between the two motions is
27 drops of mercury coalesce to form a bigger drop. What is the relative increase in surface energy?
Certain amount of an ideal gas is taken from its initial state 1 to final state 4 through the paths 1 → 2 → 3 → 4 as shown in the figure AB, CD, EF are all isotherms. If $v_p$ is the most probable speed of the molecules, then:
Certain amount of an ideal gas is taken from its initial state 1 to final
One mole of a diatomic ideal gas undergoes a process shown in the P-V diagram. The total heat given to the gas (In 2 = 0.7) is:
One mole of a diatomic ideal gas undergoes a process
If a string suspended from the ceiling is given a downward force $F_1$, its length becomes $L_1$. Its length is $L_2$ if the downward force is $F_2$. What is its actual length?
A body of mass $m$ is thrown vertically upward with speed $\sqrt{3}v_e^2$, where $v_e$ is the escape velocity of a body from earth surface. The final velocity of the body is
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
Three particles, each of mass $m$ grams situated at the vertices of an equilateral $\Delta ABC$ of side $a$ cm (as shown in the figure). The moment of inertia of the system about a line $AX$ perpendicular to $AB$ and in the plane of $\Delta ABC$ in $g$-cm² units will be:
Three particles, each of mass
Let $\Delta = \left| \begin{matrix} \sin \theta \cos \varphi & \sin \theta \sin \varphi & \cos \theta \\ \cos \theta \cos \varphi & \cos \theta \sin \varphi & -\sin \theta \\ -\sin \theta \sin \varphi & \sin \theta \cos \varphi & 0 \end{matrix} \right|$. Then
From a balloon rising vertically with uniform velocity $v$ ft/sec, a piece of stone is let go. The height of the balloon above the ground when the stone reaches the ground after 4 sec is [g = 30 ft/sec²]
Let $f(x) = x^2 + x \sin x - \cos x$. Then
Let $z_1$ and $z_2$ be two non-zero complex numbers. Then
The line $y = x + 5$ touches
Consider the equation $y - y_1 = m(x - x_1)$. If $m$ and $x_1$ are fixed, and different lines are drawn for different values of $y_1$, then
Let $R$ and $S$ be two equivalence relations on a non-void set $A$. Then
Let $p(x_0)$ be a polynomial with real coefficients, $p(0) = 1$ and $p'(x)>0$ for all $x \in \mathbb{R}$. Then
Twenty meters of wire is available to fence off a flower bed in the form of a circular sector. What must the radius of the circle be, if the area of the flower bed is greatest?
From the point $(-1, -6)$, two tangents are drawn to $y^2 = 4x$. Then the angle between the two tangents is
If $\alpha$ is a unit vector, $\beta = \hat{i} + \hat{j} - \hat{k}$, $\gamma = \hat{i} + \hat{k}$, then the maximum value of $|\alpha \beta \gamma|$ is
Chords of an ellipse are drawn through the positive end of the minor axis. Their midpoint lies on
The maximum value of $f(x) = e^{\sin x} + e^{\cos x}$, where $x \in \mathbb{R}$, is
If $x$ satisfies the inequality $\log_2 5x^2 + (\log_5 x)^2<2$, then $x$ belongs to
The value of $a$ for which the sum of the squares of the roots of the equation $x^2 - (a - 2)x - (a - 1) = 0$ assumes the least value is
The solution of $\det(A - \lambda I_2) = 0$ is $4$ and $8$, and $A = \begin{pmatrix} 2 & 3 \\ x & y \end{pmatrix}$. Then