List of top Questions asked in JEE Main

At 345 K, the half life for the decomposition of a sample of a gaseous compound initially at 55.5 kPa was 340 s. When the pressure was 27.8 kPa, the half life was found to be 170 s. The order of the reaction is ________. [integer answer]

The electronic configuration of Pt(atomic number 78) is:

\(N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)\)
Consider the above reaction, the limiting reagent of the reaction and number of moles of NH₃ formed, respectively are :

2.2 g of nitrous oxide (N₂O) gas is cooled at a constant pressure of 1 atm from 310 K to 270 K causing the compression of the gas from 217.1 mL to 167.75 mL. The change in internal energy of the process, ΔU is ‘–x’ J. The value of ‘x’ is ____. [nearest integer]
(Given : atomic mass of N = 14 g mol^–1 and of O = 16 g mol^–1
Molar heat capacity of N₂O is 100 J K^–1 mol^–1)

Let A = {1, 2, 3, 4, 5, 6, 7} and B = {3, 6, 7, 9}. Then the number of elements in the set {C ⊆ A :Cߏ∩B ≠ φ} is _____________.

A body is projected from the ground at an angle of 45° with the horizontal. Its velocity after \(2\) \(s\) is \(20\) \(ms^{–1}\). The maximum height reached by the body during its motion is ________ m. (use \(g\) = \(10\) \(ms^{–2}\))

Let the matrix \(A=\begin{bmatrix}0 & 1 & 0 \\ 0 & 0 & 1 \\ 1 & 0 & 0\end{bmatrix}\) and the matrix \(B_0=A^{49}+2 A^{98}\) If \(B_n=\text{Adj}\left(B_{n-1}\right)\) for all \(n \geq 1\), then \(\text{det}\left( B _4\right)\) is equal to :

The solubility of AgCl will be maximum in which of the following?

Among the given oxides of nitrogen; N₂O, N₂O₃, N₂O₄ and N₂O₅, the number of compound/(s) having N – N bond is:

Identify the incorrect statement from the following

An object is thrown vertically upwards. At its maximum height, which of the following quantity becomes zero?

For a specific wavelength 670 nm of light from a galaxy moving with velocity ν, the observed wavelength is 670.7 nm. The value of ν is

The velocity of upper layer of water in a river is \(36\ kmh^{–1}\). Shearing stress between horizontal layers of water is \(10^{–3} Nm^{–2}\). Depth of the river is ______ m. (Co-efficient of viscosity of water is \(10^{–2} Pa.s\))

Two buses P and Q start from a point at the same time and move in a straight line and their positions are represented by X_P(t) = αt + βt² and X_Q(t) = ft – t². At what time, both the buses have same velocity?

A bar magnetic having a magnetic moment of 2.0 × 10⁵ JT^–1, is placed along the direction of uniform magnetic field of magnitude B = 14 × 10^–5 T. The work done in rotating the magnet slowly through 60° from the direction of field is:

The positive feedback is required by an amplifier to act an oscillator. The feedback here means:

A ball is projected vertically upward with an initial velocity of 50 ms^–1 at t = 0 s. At t = 2 s, another ball is projected vertically upward with same velocity. 
At t = _____s, second ball will meet the first ball. (g = 10 ms^–2)

If a wave gets refracted into a denser medium, then which of the following is true?

The light of two different frequencies whose photons have energies 3.8 eV and 1.4 eV respectively, illuminate a metallic surface whose work function is 0.6 eV successively. The ratio of maximum speeds of emitted electrons for the two frequencies respectively will be

A parallel plate capacitor with plate area A and plate separation d = 2 m has a capacitance of 4 μF. The new capacitance of the system, if half of the space between them is filled with a dielectric material of dielectric constant K = 3 (as shown in figure), will be :

The susceptibility of a paramagnetic material is \(99\). The permeability of the material in Wb/A-m, is 
[Permeability of free space \(μ_0\) = \(4π × 10^{–7}\) Wb/A-m]

Resistance of the wire is measured as 2 Ω and 3 Ω at 10°C and 30°C respectively. Temperature co-efficient of resistance of the material of the wire is: