List of top Questions asked in JEE Main

From the following, number of compounds with \(sp^3d\) hybridisation are: \[ XeF_4,\; ICl_4^-,\; ICl_2^-,\; XeF_5^-,\; SF_4,\; XeF_2,\; ClF_3,\; BrF_5,\; NH_4^+ \]
Half life of first order reaction is \(6.93\) min. What is the time required (in min.) to complete \(99\%\) of reaction? \([\ln2 = 0.693]\)
Determine mole fraction of water in an aqueous solution of urea having \(10\%\) w/w urea.
For a first order reaction : \[ \text{A(g)} \rightarrow \text{B(g)} + \text{C(g)} \] If initial pressure is \( P_0 \) and total pressure at time \( t \) is \( P_t \), then the expression of rate constant \( K \) is:
A cube of side length \(5\,\text{cm}\) having modulus of rigidity \(10^5\,\text{N/m}^2\). The top is pulled by a force \(10\,\text{N}\) while the bottom is fixed. Find the displacement of the upper surface of cube (in mm).
If \(R=\) resistance, \(L=\) inductance, \(C=\) capacitance, then the dimension \([ML^2T^{-4}A^{-2}]\) represents
If speed of light is \(2.12\times10^8\,\text{m/s}\) in the medium of an equilateral prism, find the minimum angle of deviation.
Two points \(A\) and \(B\) are \(16\,\text{km}\) from the surface of Earth. Point \(A\) is above the surface while point \(B\) is below the surface. Acceleration due to gravity at \(A\) and \(B\) are \(g_A\) and \(g_B\) respectively. Find \(\dfrac{g_A}{g_B}\). (Take radius of Earth \(R = 6400\,\text{km}\))

LED (light emitting diode) and logic gates circuit is given in figure. For what combination of \(A,B,C\) will both LEDs glow? 

A ball is dropped from a height \(18\,\text{m}\) above the ground. At any moment, if magnitude of acceleration and velocity are same, find its height above ground at that instant.

Find the ratio of \(T_1\) and \(T_2\) for the system shown.

In the below diagram inductance \(L_1 = L_2 = L_3 = L\). Find the ratio of total energy stored in all inductors to energy stored in inductor \(L_2\). 

In a vernier caliper, 1 main scale division equals \(1\,\text{mm}\) and \(9\) MSD are divided into \(10\) equal parts by the vernier scale. When nothing was present in the jaws, zero of the vernier scale lies to the right of zero of the main scale and the \(7^{th}\) division of vernier scale coincides with one of the main scale divisions. Find zero error in the vernier caliper.

Upper wire has cross-section area \(0.008\,\text{cm}^2\) and lower wire has area \(0.004\,\text{cm}^2\). Find the maximum mass of the pan that can be connected without breaking any wire. Given breaking stress of wire is \(\sigma = 8\times10^8\,\text{N/m}^2\). 


 

For the circuit shown below, find current across \(AB\) \((I_{AB})\). 

Correct option for the circuit shown is: 

Find time taken by the block to slide a distance \(8.8\,\text{m}\) with respect to the wedge (in seconds). All surfaces are smooth. 

Displacement current inside a capacitor of capacitance \(6\,\mu F\) is \(4\,A\). Find the rate of change of voltage across the capacitor.
Moment of inertia of a rod about an axis passing through a point at distance \(\ell/4\) from the center and perpendicular to the rod is: (The uniform rod has mass \(m\) and length \(\ell\)).
In an AC circuit having \(R\) and \(C\), angular frequency \(\omega\) has peak current \(I\). If angular frequency becomes \(\omega/4\), the peak current becomes \(I/3\). Find the ratio of resistance and reactance at frequency \(\omega\).
In a region where electric field exists as \[ \vec{E} = -E_0 \hat{i} \] Initially at \(t=0\), velocity of particle of mass \(m\) is \(4v_0 \hat{i\). If de-Broglie wavelength \(\lambda_0 = \dfrac{h}{4mv_0}\), find wavelength \(\lambda\) at time \(t\).}
Identify correct statements (1) Zeroth law of thermodynamics gives concept of temperature. (2) In isothermal expansion \(\Delta Q \neq \Delta W\). (3) First law of thermodynamics gives concept of internal energy. (4) Product of intensive and extensive properties is extensive. (5) Ratio of extensive property and mass is extensive.
In a compound microscope objective and eyepiece are both biconvex lenses of focal length \(f_0\). If objective lens is cut into two halves such that a plano–convex lens is made and now it is used as objective to get same magnification, by how many times should the tube length be changed?
A charged particle is moving in a magnetic field \[ \vec B = (3\hat i + 2\hat j)\ \text{T} \] with acceleration \[ \vec a = 4\hat i - \frac{x}{2}\hat j\ \text{m/s}^2 \] Find \(x\).
In YDSE, \(\beta = 2.4\) mm where \(\beta\) is fringe width. If the setup is dipped in a medium of refractive index \(\mu = 1.2\), find the new fringe width (in mm).