List of top Questions asked in JEE Main

Given below are two statement : one is labelled as Assertion A and the other is labelled as Reason R :

Assertion A : Size of Bk\(^{3+}\) ion is less than Np\(^{3+}\) ion.

Reason R : The above is a consequence of the lanthanoid contraction.

In the light of the above statements, choose the correct answer from the options given below :

Which among the following pairs of Vitamins is stored in our body relatively for longer duration?

In the above chemical reaction, intermediate "X" and reagent/condition "A" are :

Assertion A : Enol form of acetone \([\mathrm{CH_3COCH_3}]\) exists in < 0.1% quantity. However, the enol form of acetyl acetone \([\mathrm{CH_3COCH_2OCCH_3}]\) exists in approximately 15% quantity.

Reason R : Enol form of acetyl acetone is stabilized by intramolecular hydrogen bonding, which is not possible in enol form of acetone.

Choose the correct statement :

Among the following, the aromatic compounds are :

Choose the correct answer from the following options :

In chromotography technique, the purification of compound is independent of :

Given below are two statements :

Statement I : The E^o value for Ce⁴⁺ / Ce³⁺ is + 1.74 V.

Statement II : Ce is more stable in Ce⁴⁺ state than Ce³⁺ state.

In the light of the above statements, choose the most appropriate answer from the options given below :

In the logic circuit shown in the figure, if input A and B are 0 to 1 respectively, the output at Y would be 'x'.
The value of x is ____________.

The product "P" in the above reaction is :

Given below are two statements : one is labeled as Assertion A and the other is labelled as Reason R :

Assertion A : The H\(-\)O\(-\)H bond angle in water molecule is \(104.5^\circ\).

Reason R : The lone pair - lone pair repulsion of electrons is higher than the bond pair - bond pair repulsion.

In the light of the above statements, choose the correct answer from the options given below :

A ball of mass 10 kg moving with a velocity \(10\sqrt{3}\ \mathrm{m\,s^{-1}}\) along X-axis, hits another ball of mass 20 kg which is at rest. After collision, the first ball comes to rest and the second one disintegrates into two equal pieces. One of the pieces starts moving along Y-axis at a speed of 10 m/s. The second piece starts moving at a speed of 20 m/s at an angle \(\theta\) (degree) with respect to the X-axis.
The configuration of pieces after collision is shown in the figure.

The value of \(\theta\) to the nearest integer is ____________.

A sinusoidal voltage of peak value 250 V is applied to a series LCR circuit, in which R = 8 \(\Omega\), L = 24 mH and C = 60 \(\mu\)F. The value of power dissipated at resonant condition is 'x' kW. The value of x to the nearest integer is ____________.

Consider a frame that is made up of two thin massless rods AB and AC as shown in the figure. A vertical force \(\vec{P}\) of magnitude 100 N is applied at point A of the frame.

Suppose the force \(\vec{P}\) is resolved parallel to the arms AB and AC of the frame.
The magnitude of the resolved component along the arm AC is x N.
The value of x, to the nearest integer, is ___________.
[Given : \(\sin(35^\circ) = 0.573\), \(\cos(35^\circ) = 0.819\), \(\sin(110^\circ) = 0.939\), \(\cos(110^\circ) = -0.342\)]

In the figure given, the electric current flowing through the 5 \(\mathrm{k\Omega}\) resistor is 'x' mA.

The value of x to the nearest integer is ____________.

Consider a 20 kg uniform circular disk of radius 0.2 m. It is pin supported at its center and is at rest initially. The disk is acted upon by a constant force F = 20 N through a massless string wrapped around is periphery as shown in the figure.

Suppose the disk makes n number of revolutions to attain an angular speed of 50 rad s^-1.
The value of n, to the nearest integer, is __________.
[Given : In one complete revolution, the disk rotates by 6.28 rad]

A fringe width of 6 mm was produced for two slits separated by 1 mm apart. The screen is placed 10 m away. The wavelength of light used is 'x' nm. The value of 'x' to the nearest integer is ____________.

The resistance \(R = \frac{V}{I}\), where V = \((50 \pm 2)\) V and I = \((20 \pm 0.2)\) A. The percentage error in R is 'x'%. The value of 'x' to the nearest integer is _________.

A 25 m long antenna is mounted on an antenna tower. The height of the antenna tower is 75 m. The wavelength (in meter) of the signal transmitted by this antenna would be :

The value of power dissipated across the zener diode (V_z = 15V) connected in the circuit as shown in the figure is x \(\times\) 10^-1 watt.

The value of x, to the nearest integer, is __________.

An RC circuit as shown in the figure is driven by a AC source generating a square wave. The output wave pattern monitored by CRO would look close to :

For an electromagnetic wave travelling in free space, the relation between average energy densities due to electric (\(U_e\)) and magnetic (\(U_m\)) fields is :

The stopping potential in the context of photoelectric effect depends on the following property of incident electromagnetic radiation :

One main scale division of a vernier callipers is 'a' cm and \(n^{\text{th}}\) division of the vernier scale coincide with \((n - 1)^{\text{th}}\) division of the main scale. The least count of the callipers in mm is :

A conducting bar of length L is free to slide on two parallel conducting rails as shown in the figure

Two resistors R₁ and R₂ are connected across the ends of the rails. There is a uniform magnetic field \(\vec{B}\) pointing into the page. An external agent pulls the bar to the left at a constant speed v.
The correct statement about the directions of induced currents I₁ and I₂ flowing through R₁ and R₂ respectively is :

A bar magnet of length 14 cm is placed in the magnetic meridian with its north pole pointing towards the geographic north pole. A neutral point is obtained at a distance of 18 cm from the center of the magnet. If B_H = 0.4 G, the magnetic moment of the magnet is : (\(1\,\text{G} = 10^{-4}\) T)