List of top Questions asked in JEE Main

The mechanism of action of "Terfenadine" (Seldane) is :

The reaction in which the hybridisation of the underlined atom is affected is :

The molecule in which hybrid MOs involve only one d-orbital of the central atom is :

The Crystal Field Stabilization Energy (CFSE) of \([\mathrm{CoF_3(H_2O)_3}]\) (\(\Delta_0 \lt P\)) is :

The one that can exhibit highest paramagnetic behaviour among the following is :
gly = glycinato; bpy = 2, 2'-bipyridine

The major product [R] in the following sequence of reactions as :
\(\mathrm{HC{\equiv}CH}\ \xrightarrow[\mathrm{(ii)\ (CH_3)_2CH{-}CH(CH_3){-}Br}]{\mathrm{(i)\ LiNH_2/ether}}\ \mathrm{[P]}\ \xrightarrow[\mathrm{(ii)\ NaBH_4}]{\mathrm{(i)\ HgSO_4/H_2SO_4}}\ \mathrm{[Q]}\ \xrightarrow[\Delta]{\mathrm{Conc.\ H_2SO_4}}\ \mathrm{[R]}\)

The major product [B] in the following reactions is :
\(\mathrm{CH_3CH_2{-}CH(CH_3){-}CH_2{-}O{-}CH_2{-}CH_3}\ \xrightarrow[\mathrm{Heat}]{\mathrm{HI}}\ \mathrm{[A]\ alcohol}\ \xrightarrow[\Delta]{\mathrm{H_2SO_4}}\ \mathrm{[B]}\)

250 mL of a waste solution obtained from the workshop of a goldsmith contains 0.1 M AgNO₃ and 0.1 M AuCl. The solution was electrolyzed at 2V by passing a current of 1A for 15 minutes. The metal/metals electrodeposited will be
[ \(E^0_{Ag^+/Ag} = 0.80\ \mathrm{V}\), \(E^0_{Au^+/Au} = 1.69\ \mathrm{V}\) ]

The incorrect statement(s) among (a) - (c) is (are)
(a) W(VI) is more stable than Cr(VI).
(b) In the presence of HCl, permanganate titrations provide satisfactory results.
(c) Some lanthanoid oxides can be used as phosphors.

Five moles of an ideal gas at 1 bar and 298 K is expanded into vacuum to double the volume. The work done is :

The change in the magnitude of the volume of an ideal gas when a small additional pressure \(\Delta P\) is applied at a constant temperature, is the same as the change when the temperature is reduced by a small quantity \(\Delta T\) at constant pressure. The initial temperature and pressure of the gas were 300 K and 2 atm. respectively.
If \(|\Delta T| = C|\Delta P|\) then value of C in (K/atm.) is _________.

If the equilibrium constant for \(\mathrm{A \rightleftharpoons B + C}\) is \(K_{eq}^{(1)}\) and that of \(\mathrm{B + C \rightleftharpoons P}\) is \(K_{eq}^{(2)}\), the equilibrium constant for \(\mathrm{A \rightleftharpoons P}\) is :

The driver of a bus approaching a big wall notices that the frequency of his bus's horn changes from 420 Hz to 490 Hz when he hears it after it gets reflected from the wall. Find the speed of the bus if speed of the sound is 330 ms^-1.

Orange light of wavelength \(6000\times10^{-10}\) m illuminates a single slit of width \(0.6\times10^{-4}\) m. The maximum possible number of diffraction minima produced on both sides of the central maximum is ___________.

A circular coil has moment of inertia 0.8 kg m² around any diameter and is carrying current to produce a magnetic moment of 20 Am². The coil is kept initially in a vertical position and it can rotate freely around a horizontal diameter. When a uniform magnetic field of 4 T is applied along the vertical, it starts rotating around its horizontal diameter. The angular speed the coil acquires after rotating by \(60^\circ\) will be:

A person pushes a box on a rough horizontal plateform surface. He applies a force of 200 N over a distance of 15 m. Thereafter, he gets progressively tired and his applied force reduces linearly with distance to 100 N. The total distance through which the box has been moved is 30 m. What is the work done by the person during the total movement of the box?

A series L-R circuit is connected to a battery of emf V. If the circuit is switched on at t = 0, then the time at which the energy stored in the inductor reaches \(\left(\dfrac{1}{n}\right)\) times of its maximum value, is :

Match the thermodynamic processes taking place in a system with the correct conditions. In the table : \(\Delta Q\) is the heat supplied, \(\Delta W\) is the work done and \(\Delta U\) is change in internal energy of the system.

Process	Condition
(I) Adiabatic	(1) \(\Delta W = 0\)
(II) Isothermal	(2) \(\Delta Q = 0\)
(III) Isochoric	(3) \(\Delta U \neq 0,\ \Delta W \neq 0,\ \Delta Q \neq 0\)
(IV) Isobaric	(4) \(\Delta U = 0\)

A paramagnetic sample shows a net magnetisation of 6 A/m when it is placed in an external magnetic field of 0.4 T at a temperature of 4 K. When the sample is placed in an external magnetic field of 0.3 T at a temperature of 24 K, then the magnetisation will be:

The electric field of a plane electromagnetic wave is given by
\(\vec{E} = E_0(\hat{x} + \hat{y})\sin(kz - \omega t)\)
Its magnetic field will be given by :

A test consists of 6 multiple choice questions, each having 4 alternative answers of which only one is correct. The number of ways, in which a candidate answers all six questions such that exactly four of the answers are correct, is __________.

A small ball of mass m is thrown upward with velocity u from the ground. The ball experiences a resistive force \(mkv^2\) where v is its speed. The maximum height attained by the ball is :

Consider two uniform discs of the same thickness and different radii \(R_1 = R\) and \(R_2 = \alpha R\) made of the same material. If the ratio of their moments of inertia \(I_1\) and \(I_2\), respectively, about their axes is \(I_1 : I_2 = 1 : 16\) then the value of \(\alpha\) is :

A body is moving in a low circular orbit about a planet of mass M and radius R. The radius of the orbit can be taken to be R itself. Then the ratio of the speed of this body in the orbit to the escape velocity from the planet is:

The circle passing through the intersection of the circles,
\(x^2 + y^2 - 6x = 0\) and \(x^2 + y^2 - 4y = 0\), having its centre on
the line, \(2x - 3y + 12 = 0\), also passes through the point :