List of top Physics Questions asked in WBJEE

A body floats with $\frac{1}{n}$ of its volume keeping outside of water. If the body has been taken to height $h$ inside water and released, it will come to the surface after time $t$. Then:

Two convex lenses ($L_1$ and $L_2$) of equal focal length $f$ are placed at a distance $\frac{f}{2}$ apart. An object is placed at a distance $4f$ to the left of $L_1$ as shown in the figure. The final image is at:

The speed distribution for a sample of $N$ gas particles is shown below. $P(v) = 0$ for $v > 2v_0$. How many particles have speeds between $1.2v_0$ and $1.8v_0$?

In the given network of AND and OR gates, output Q can be written as (assuming n even):

A beam of light of wavelength $\lambda$ falls on a metal having work function $\phi$ placed in a magnetic field $B$. The most energetic electrons, perpendicular to the field, are bent in circular arcs of radius $R$. If the experiment is performed for different values of $\lambda$, then the $B^2 \, \text{vs} \, \frac{1}{\lambda}$ graph will look like (keeping all other \textbf{quantities constant}).

The variation of impedance Z of a series LCR circuit with frequency of the source is shown in the figure. Which of the following statement(s) is/are true?

A small sphere of mass m and radius R slides down the smooth surface of a large hemispherical bowl of radius R. If the sphere starts sliding from rest, the total kinetic energy of the sphere at the lowest point A of the bowl will be:

If $\vec{n}_1$, $\vec{n}_2$, and $\vec{i}$ represent unit vectors along the incident ray, reflected ray, and normal to the surface, respectively, then:

Three point charges $q, -2q$, and $q$ are placed along the $x$-axis at $x = -a, 0,$ and $a$, respectively. As $a \to 0$ and $q \to \infty$, while $qa^2 = Q$ remains finite, the electric field at a point $P$, at a distance $x \gg a$ from $x = 0$, is given by: $$\vec{E} = \frac{qQ}{4 \pi \epsilon_0 x^3} \hat{i}.$$ Then, find the relationship between $\alpha$ and $\beta$.

Water is filled in a cylindrical vessel of height H. A hole is made at height z from the bottom, as shown in the figure. The value of z for which the range R of the emerging water through the hole will be maximum for:

Consider a circuit where a cell of emf $E_0$ and internal resistance $r$ is connected across the terminal A and B as shown in the figure. The value of $R$ for which the power generated in the circuit is maximum, is given by:

A metal plate of area 10^-2m² rests on a layer of castor oil, 2 × 10^-3m thick, whose coefficient of viscosity is 1.55 Ns/m². The approximate horizontal force required to move the plate with a uniform speed of 3 × 10^-2ms^-1 is:

Light of wavelength $6000 \, \text{Å}$ is incident on a thin glass plate of refractive index $1.5$ such that the angle of refraction into the plate is $60^\circ$. Calculate the smallest thickness of the plate which will make a dark fringe by reflected beam interference.

A small ball of mass m is suspended from the ceiling of a floor by a string of length L. The ball moves along a horizontal circle with constant angular velocity ω, as shown in the figure. The torque about the center (O) of the horizontal circle is:

The displacement of a plane progressive wave in a medium, traveling towards the positive x-axis with velocity 4m/s at t=0 is given by $y=3sin2\pi(-\frac{x}{3})$. Then the expression for the displacement at a later time t=4 sec will be

Three identical convex lenses each of focal length f are placed in a straight line separated by a distance f from each other. An object is located in $\frac{f}{2}$ in front of the leftmost lens. Then,

In an experiment on a circuit, as shown in the figure, the voltmeter shows 8V reading. The resistance of the voltmeter is 

A charged particle in a uniform magnetic field $\vec{B}=B_0\hat{k}$ starts moving from the origin with velocity $v=3\hat{i}+4\hat{k}$ m/s.The trajectory of the particle and the time $t$ at which it reaches 2m above the x-y plane are 

A given quantity of gas is taken from A to C in two ways; a) directly from A$\rightarrow$C along a straight line and b) in two steps, from A$\rightarrow$B and then from B$\rightarrow$C.Work done and heat absorbed along the direct path A$\rightarrow$C are 200J and 280J respectively. If the work done along A$\rightarrow$B$\rightarrow$C is 80J, then heat absorbed along the path is,

A train is moving along the tracks at a constant speed u. A girl on the train throws a ball of mass m straight ahead along the direction of motion of the train with speed v with respect to herself. Then,

In the given circuit, find the voltage drop V_L in the load resistance R_L

In an experiment, the length of an object is measured to be 6.50 cm. This measured value can be written as 0.0650 m.The number of significant figures on 0.0650m is

X-rays of wavelength λ get reflected from parallel planes of atoms in a crystal with spacing d between two planes as shown in the figure. If the two reflected beams interfare constructively,Then the condition for maxima will be(n is the order of interference fringe)