List of top Physics Questions asked in WBJEE

Two infinite line charges parallel to each other are moving with a constant velocity $v$ in the same direction as shown in the figure. The separation between two line charges is $d$. The magnetic attraction balances the electric repulsion when, [e = speed of light in free space]
Two infinite line charges parallel to each other are moving with
Consider a thermodynamic process where internal energy $U \equiv A p^2 V$ (A = Constant). If the process is performed adiabatically, 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
A Zener diode having a breakdown voltage $V_z = 6$ V is used in a voltage regulator circuit as shown in the figure. The minimum current required to pass through the Zener to act as a voltage regulator is $10$ mA and the maximum allowed current through the Zener is $40$ mA. The maximum value of $R_\delta$ for Zener to act as a voltage regulator is
A Zener diode having a breakdown voltage
One mole of an ideal monatomic gas expands along the polytrope $P V^3 = \text{constant}$ from $V_1$ to $V_2$ at a constant pressure $P_1$. The temperature during the process is such that molar specific heat $C_v = \frac{3R}{2}$. The total heat absorbed during the process can be expressed as
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
A particle is moving in the $x$-$y$ plane according to $r = b \cos \omega t \hat{i} + b \sin \omega t \hat{j}$. Where $\omega$ is constant. Which of the following statement(s) is/are true?
The kinetic energy ($E_k$) of a particle moving along the X-axis varies with its position ($X$) as shown in the figure. The force acting on the particle at $X = 10$ m is
particle moving along the X-axis varies with its position
A horizontal semi-circular wire of radius $r$ is connected to a battery through two similar springs $X$ and $Y$ to an electric cell, which sends current $I$ through it. A vertically downward uniform magnetic field $B$ is applied on the wire, as shown in the figure. What is the force acting on each spring?
A horizontal semi-circular wire of radius
Consider two concentric conducting spheres of radii $R$ and $2R$ respectively. The inner sphere is given a charge $+Q$. The other sphere is grounded. The potential at $r = \frac{3R}{2}$ is
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
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
Three concentric metallic shells $A$, $B$, and $C$ of radii $a$, $b$, and $c$ have surface charge densities $+\sigma$, $-\sigma$, and $\sigma+$ respectively. The potential of shell $B$ is
Three concentric metallic shells
A particle is moving in an elliptical orbit as shown in the figure. If $p$, $L$, and $r$ denote the linear momentum, angular momentum, and position vector of the particle (from focus $O$) respectively at a point $A$, then the direction of $\alpha = p \times L$ is along
particle is moving in an elliptical orbit
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
The Entropy ($S$) of a black hole can be written as $S = \beta k_B A$, where $k_B$ is the Boltzmann constant and $A$ is the area of the black hole. Then $\beta$ has dimension of
Find the equivalent capacitance between $A$ and $B$ of the following arrangement:
equivalent capacitance
A capacitor of capacitance $'C'$, is connected across an ac source of voltage $V$, given by $V = V _{0} \sin \omega t$ The displacement current between the plates of the capacitor, would then be given by:
The ratio of magnetic field and magnetic moment at the centre of a current carrying circular loop is $x$. When both the current and radius is doubled the ratio will be
A body starts from rest, under the action of an engine working at a constant power and moves along a straight line. The displacement S is given as a function of time (t) as
An electric current ?I? enters and leaves a uniform circular wire of radius r through dfiametrically opposite points. A particle carrying a charge q moves along the axis of the circular wire with speed v. What is the magnetic force experienced by the particle when it passes through the centre of the circle ?
A projectile thrown with an initial velocity of 10 ms$^-1$ at an angle $\alpha$ with the horizontal, has a range of 5 m. Taking g = 10 ms$^-2 $and neglecting air resistance, what will be the estimated value of $\alpha$ ?
A compressive force is applied to a uniform rod of rectangular cross-section so that its length decreases by 1%. If the Poisson?s ratio for the material of the rod be 0.2, which of the following statements is correct ? "The volume approximately ....."
Assume that the earth moves around the sun in a circular orbit of radius R and there exists a planet which also moves around the sun in circular orbit with an angular speed twice as large as that of the earth. The radius of the orbit of the planet is
The initial pressure and volume of a given mass of an ideal gas $\left(with\frac{C_{p}}{C_{v}} =\gamma\right),$ taken in a cylinder fitted with a piston, are P$ _0$ and V$_0$ respectively. At this stage the gas has the same temperature as that of the surrounding medium which is T$_0$. It is adiabatically compressed to a volume equal to $\frac{v_{0}}{2}.$ Subsequently the gas is allowed to come to thermal equilibrium with the surroundings. What is the heat released to the surroundings ?