List of top Questions asked in JEE Main

The major product of the following reaction is :

The organic compound that gives following qualitative analysis is :

	Test	Inference
(a)	Dil. HCl	Insoluble
(b)	NaOH solution	soluble
(c)	\(\mathrm{Br_2}\)/water	Decolourization

The given plots represent the variation of the concentration of a reactant R with time for two different reactions (i) and (ii). The respective orders of the reactions are :

Which of the following statements is not true about sucrose?

Among the following, the molecule expected to be stabilized by anion formation is :
\(\mathrm{C_2,\ O_2,\ NO,\ F_2}\)

The major product of the following reaction is :

A signal \(A\cos\omega t\) is transmitted using \(v_0\sin\omega_0 t\) as carrier wave. The correct amplitude modulated (AM) signal is

Liquid 'M' and liquid 'N' form an ideal solution. The vapour pressures of pure liquids 'M' and 'N' are 450 and 700 mmHg, respectively, at the same temperature. Then correct statement is:
(\(x_M\) = Mole fraction of 'M' in solution ;
\(x_N\) = Mole fraction of 'N' in solution ;
\(y_M\) = Mole fraction of 'M' in vapour phase ;
\(y_N\) = Mole fraction of 'N' in vapour phase)

The major product of the following reaction is :
\(\mathrm{CH_3CH=CHCO_2CH_3}\ \xrightarrow{\ \mathrm{LiAlH_4}\ }\ ?\)

An NPN transistor is used in common emitter configuration as an amplifier with \(1\ \mathrm{k}\Omega\) load resistance. Signal voltage of 10 mV is applied across the base-emitter. This produces a 3 mA change in the collector current and \(15\mu\mathrm{A}\) change in the base current of the amplifier. The input resistance and voltage gain are :

The degenerate orbitals of \([\mathrm{Cr(H_2O)_6}]^{3+}\) are :

A capacitor with capacitance \(5\mu\mathrm{F}\) is charged to \(5\mu\mathrm{C}\). If the plates are pulled apart to reduce the capacitance to \(2\mu\mathrm{F}\), how much work is done ?

The stream of a river is flowing with a speed of 2 km/h. A swimmer can swim at a speed of 4 km/h. What should be the direction of the swimmer with respect to the flow of the river to cross the river straight ?

A simple pendulum oscillating in air has period \(T\). The bob of the pendulum is completely immersed in a non-viscous liquid. The density of the liquid is 1/16 th of the material of the bob. If the bob is inside liquid all the time, its period of oscillation in this liquid is :

The total number of turns and cross-section area in a solenoid is fixed. However, its length \(L\) is varied by adjusting the separation between windings. The inductance of solenoid will be proportional to :

A stationary horizontal disc is free to rotate about its axis. When a torque is applied on it, its kinetic energy as a function of \(\theta\), where \(\theta\) is the angle by which it has rotated, is given as \(k\theta^2\). If its moment of inertia is \(I\) then the angular acceleration of the disc is :

The electric field of light wave is given as
\(\vec{E}=10^{-3}\cos\left(\frac{2\pi x}{5\times10^{-7}}-2\pi\times6\times10^{14}t\right)\hat{x}\ \frac{\mathrm{N}}{C}\)
This light falls on a metal plate of work function 2 eV. The stopping potential of the photoelectrons is :
Given, \(E\) (in eV) \(=12375/\lambda\) (in \(\mathrm{\AA}\))

The figure shows a Young's double slit experimental setup. It is observed that when a thin transparent sheet of thickness \(t\) and refractive index \(\mu\) is put in front of one of the slits, the central maximum gest shifted by a distance equal to \(n\) fringe widths. If the wavelength of light used is \(\lambda\), \(t\) will be :

The following bodies are made to roll up (without slipping) the same inclined plane from a horizontal plane. : (i) a ring of radius \(R\), (ii) a solid cylinder of radius \(R/2\) and (iii) a solid sphere of radius \(R/4\). If in each case, the speed of the centre of mass at the bottom of the incline is same, the ratio of the maximum heights they climb is :

In the density measurement of a cube, the mass and edge length are measured as \((10.00\pm0.10)\) kg and \((0.10\pm0.01)\) m, respectively. The error in the measurement of density is :

A concave mirror for face viewing has focal length of 0.4 m. The distance at which you hold the mirror from your face in order to see your image upright with a magnification of 5 is :

A system of three charges are placed as shown in the figure :

If \(D \gg d\), the potential energy of the system is best given by :

A rectangular coil (Dimension \(5\ \mathrm{cm} \times 2.5\ \mathrm{cm}\)) with 100 turns, carrying a current of 3 A in the clock-wise direction is kept centered at the origin and in the X-Z plane. A magnetic field of 1 T is applied along X-axis. If the coil is tilted through \(45^\circ\) about Z-axis, then the torque on the coil is :

A moving coil galvanometer has resistance \(50\ \Omega\) and it indicates full deflection at 4 mA current. A voltmeter is made using this galvanometer and a \(5\ \mathrm{k\Omega}\) resistance. The maximum voltage, that can be measured using this voltmeter, will be close to :

A wire of resistance \(R\) is bent to form a square ABCD as shown in the figure. The effective resistance between E and C is : (E is mid-point of arm CD)