List of top Questions asked in JEE Main

For the cell \(\mathrm{Zn(s)\,|\,Zn^{2+}(aq)\,||\,M^{x+}(aq)\,|\,M(s)}\), different half cells and their standard electrode potentials are given below :

\(\mathrm{M^{x+}(aq)/M(s)}\)	\(\mathrm{Au^{3+}(aq)/Au(s)}\)	\(\mathrm{Ag^{+}(aq)/Ag(s)}\)	\(\mathrm{Fe^{3+}(aq)/Fe^{2+}(aq)}\)	\(\mathrm{Fe^{2+}(aq)/Fe(s)}\)
\(E^\circ_{M^{x+}/M}\) (V)	1.40	0.80	0.77	\(-0.44\)

If \(E^\circ_{\mathrm{Zn^{2+}/Zn}} = -0.76\) V, which cathode will give maximum value of \(E^\circ_{cell}\) per electron transferred?

The element that usually does NOT show variable oxidation states is :

The major product of the following reaction is :

The major product of the following reaction is :

The freezing point of a diluted milk sample is found to be \(-0.2^\circ\)C, while it should have been \(-0.5^\circ\)C for pure milk. How much water has been added to pure milk to make the diluted sample?

The correct match between items I and II is :

Item-I (Mixture)	Item-II (Seperation method)
(A) \(\mathrm{H_2O}\) : Sugar	(P) Sublimation
(B) \(\mathrm{H_2O}\) : Aniline	(Q) Recrystallization
(C) \(\mathrm{H_2O}\) : Toluene	(R) Steam distillation
	(S) Differential extraction

Among the following compounds, which one is found in RNA ?

Two blocks of the same metal having same mass and at temperature \(T_1\) and \(T_2\), respectively, are brought in contact with each other and allowed to attain thermal equilibrium at constant pressure. The change in entropy, \(\Delta S\), for this process is :

In a Young's double slit experiment, the path difference, at a certain point on the screen, between two interfering waves is \(\frac{1}{8}\) th of wavelength. The ratio of the intensity at this point to that at the centre of a bright fringe is close to :

A gas mixture consists of 3 moles of oxygen and 5 moles of argon at temperature T. considering only translational and rotational modes, the total internal energy of the system is :

In an experiment, electrons are accelerated, from rest, by applying a voltage of 500 V. Calculate the radius of the path if a magnetic field 100 mT is then applied. [Charge of the electron = \(1.6 \times 10^{-19}\) C Mass of the electron = \(9.1 \times 10^{-31}\) kg]

Consider the reaction
\(\mathrm{N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)}\)

The equilibrium constant of the above reaction is \(K_p\). If pure ammonia is left to dissociate, the partial pressure of ammonia at equilibrium is given by (Assume that \(P_{NH_3} \ll P_{total}\) at equilibrium)

A body is projected at t = 0 with a velocity 10 ms\(^{-1}\) at an angle of \(60^\circ\) with the horizontal. The radius of curvature of its trajectory at t = 1s is R. neglecting air resistance and taking acceleration due to gravity g = 10 ms\(^{-2}\), the value of R is :

The force of interaction between two atoms is given by \(F = \alpha\beta\exp\left(-\frac{x^2}{\alpha kt}\right)\); where \(x\) is the distance, \(k\) is the Boltzmann constant and \(T\) is temperature and \(\alpha\) and \(\beta\) are two constants. The dimension of \(\beta\) is :

An electromagnetic wave of intensity 50 Wm\(^{-2}\) enters in a medium of refractive index 'n' without any loss. The ratio of the magnitudes of electric, and the ratio of the magnitudes of magnetic fields of the wave before and after entering into the medium are respectively, given by:

An object is at a distance of 20 m from a convex lens of focal length 0.3 m. The lens forms an image of the object. If the object moves away from the lens at a speed of 5 m/s, the speed and direction of the image will be :

If the de Broglie wavelength of an electron is equal to the \(10^{-3}\) times the wavelength of a photon of frequency \(6 \times 10^{14}\) Hz, then the speed of electron is equal to : (Speed of light = \(3 \times 10^{8}\) m/s, Planck's constant = \(6.63 \times 10^{-34}\) J.s, Mass of electron = \(9.1 \times 10^{-31}\) kg)

A liquid of density \(\rho\) is coming out of a hose pipe of radius \(a\) with horizontal speed \(v\) and hits a mesh. 50% of the liquid passes through the mesh unaffected. 25% looses all of its momentum and 25% comes back with the same speed. The resultant pressure on the mesh will be :

A slab is subjected to two forces \(\vec{F_1}\) and \(\vec{F_2}\) of same magnitude \(F\) as shown in the figure. Force \(\vec{F_2}\) is in XY-plane while force \(\vec{F_1}\) acts along z-axis at the point \((2\hat{i} + 3\hat{j})\). The moment of these forces about point O will be :

A particle is moving along a circular path with a constant speed of \(10\ \mathrm{ms^{-1}}\). What is the magnitude of the change in velocity of the particle, when it moves through an angle of \(60^\circ\) around the centre of the circle?

Three charges \(Q\), \(+q\) and \(+q\) are placed at the vertices of a right-angle isosceles triangle as shown below. The net electrostatic energy of the configuration is zero, if the value of \(Q\) is :

The given graph shows variation (with distance \(r\) form centre) of :

An equilateral triangle ABC is cut from a thin solid sheet of wood. (see figure) D, E and F are the mid-points of its sides as shown and G is the centre of the triangle. The moment of inertia of the triangle about an axis passing through G and perpendicular to the plane of the triangle is \(I_0\). If the smaller triangle DEF is removed from ABC, the moment of inertia of the remaining figure about the same axis is I. then :

In a Wheatstone bridge (see fig.), Resistances \(P\) and \(Q\) are approximately equal. When \(R = 400\ \Omega\), the bridge is balanced. On interchanging \(P\) and \(Q\), the value of \(R\), for balance, is \(405\ \Omega\). The value of \(X\) is close to :

The direction ratios of normal to the plane through the points \((0, -1, 0)\) and \((0, 0, 1)\) and making an angle \(\frac{\pi}{4}\) with the plane \(y - z + 5 = 0\) are :