List of top Questions asked in WBJEE

A satellite of mass \(m\) rotates round the earth in a circular orbit of radius \(R\). If the angular momentum of the satellite is \(J\), then its kinetic energy (\(K\)) and the total energy (\(E\)) of the satellite are:

Equal volumes of aqueous solution of 0.1 M HCl and 0.2 M H₂SO₄ are mixed. The concentration of H+ ions in the resulting solution is:

The following figure shows the variation of potential energy V (x) of a particle with distance x. The particle has:

Longitudinal waves cannot:

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:

The elastic potential energy of a strained body is:

For a spontaneous process, the incorrect statement is:

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:

The electric field of a plane electromagnetic wave in a medium is given by

where c is the speed of light in free space. E field is polarized in the x −z plane. The speed of the wave is v in the medium. Then:

Two straight conducting plates form an angle θ where their ends are joined. A conducting bar in contact with the plates and forming an isosceles triangle with them, starts at the vertex at time t = 0 and moves with constant velocity v to the right as shown in the figure. A magnetic field B points out of the page. The magnitude of emf induced at t = 1 second will be:

pH of 10⁻⁸ M HCl solution 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.

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:

The compressibility factor for a van der Waals gas at high pressure is

Consider an electron moving in the first Bohr orbit of a He\(^+\) ion with velocity \(v_1\). If it is allowed to move in the third Bohr orbit with velocity \(v_3\), determine the correct \(v_3 : v_1\) ratio.\\

The compound that does not give a positive test for nitrogen in Lassaigne’s test is

Correct solubility order of AgF, AgCl, AgBr, AgI in water is:

What will be the change in acidity if:
(i) CuSO₄ is added to saturated (NH₄)₂SO₄ solution,
(ii) SbF₅ is added to anhydrous HF?

The internal energy of a thermodynamic system is given by \( U = a s^{4/3} v^\alpha \), where \( s \) is entropy, \( v \) is volume, and \( a \) and \( \alpha \) are constants. The value of \( \alpha \) is:

The correct acidity order of phenol (I), 4-hydroxybenzaldehyde (II), and 3-hydroxybenzaldehyde (III) is:

In a series LCR circuit, the rms voltage across the resistor and the capacitor are \(30 \, \text{V}\) and \(90 \, \text{V}\) respectively. If the applied voltage is \(50\sqrt{2}\sin\omega t\), then the peak voltage across the inductor is:

After the emission of a β-particle followed by an α-particle from \(^{214}_{83}\text{Bi}\), the number of neutrons in the atom is: