List of top Questions asked in JEE Main

If the length of a conductor is increased by 20% and cross-sectional area is decreased by 4% ,then calculate the percentage change in the resistance of the conductor.

How many moles of $Ba_3(PO_4)_2$ will be formed by the reaction of $5$ moles of $BaCl_2$ and $3$ moles of $Na_3(PO_4)$.

How many bromo products are formed when ethane is reacted with excess of $Br_2$ on heating?

Assertion (A) : Radius of H+ is 1.5 × 10^–3 pm.
Reason (R) : H+ cannot exist independently.

A wire of length 2 m, radius of cross-section 20 mm and Young's Modulus 2×10¹¹ N/m is subjected to a force of 62.8 kN.The change in length of the wire is p×10^–5 (in m). Find P.

Area bounded by the curve 2y² = 3x and the line x+y = 3 outside the circle (x-3)² + y² = 2 and above the x-axis is A. The value of 4(π +4A) is?

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
A ⇒ Spin only magnetic moment of [Fe(CN)₆]^–3 is 1.73 B.M. and [Fe(H₂O)₆]⁺³ is 5.92 B.M.
R ⇒ In both cases Fe have +3 oxidation state
In the light of the above statements, write the detailed answer:

Given below are two statement: one is labelled as Assertion (A) and the other is labelled as Reason (R).
$A ⇒$ Spin only magnetic moment of $[Fe(CN)_6]^{–3}$ is $1.73$ B.M. and $[Fe(H_2O)_6]^{+3}$ is $5.92$ B.M.
$R ⇒$ In both cases Fe have $+3$ oxidation state.
In the light of the above statements, write the detailed answer:

For a metal ion magnetic moment is calculated to be 4.9BM. Find the number of unpaired.

For a first-order reaction, if the value of $t_{\frac{1}{2}}$ is T, then the value of $t_{\frac{7}{8}}$ will be_____ T.

Find the number of atoms per unit cell if edge length is 300pm, density = 3 g/cm³ , molecular mass = 40 g(nearest integer)

Find out difference in oxidation state of Xe in completely Hydrolysed form of XeF₄ and XeF₆

A particle is projected at an angle of 30° with ground with speed 40 m/s. The speed of the particle after 2 s is (use g=10 ms^-2)

2 gm of x is present in 1 mole of H₂O.Find the mass % of x

A block of mass 100 gm is placed on a smooth surface, moves with acceleration of a=2x, then the change in kinetic energy can be given as $\left(\frac{x^n}{10}\right)$. Find the value of n.

A car is moving with a speed of 15 m/s towards a stationary wall. A person in the car pressed the horn and experienced the change in frequency of 40 Hz due to reflection from the stationary wall. Find the frequency of the horn.
(Use $𝑣_{sound}$ = 330 m/s)

A body is rotating with kinetic energy E. If angular velocity of body is increased to three times of initial angular velocity then kinetic energy become nE. Find n.

25% of 250g sugar solution & 40% of 500g sugar solution are mixed then find out the mass percentage in the solution.

Find the spin magnetic moment ratio for complexes $[Cr(Cn)_{6}]^{-3}$ & $[Cr(H_{2}O)_{6}]^{+3}$

By weight, 23% NaCl and 19.5% MgCl₂ are present in salt water. The degree of dissociation of both salts is 100%. Find the average boiling point of salt water (inºC). (Kb = 0.52 K kg mol^–1) (Nearest integer)

NH₃, NO, N₂, F₂, CO, CO₂, H₂O, and XeF₄. Fill the number of above molecules having only two lone pair of electrons.

K_sp of BaSO₄ is 8 × 10^–11. If the solubility in presence of 0.1 M CaSO₄ is?

5 boys with allotted roll numbers and seat numbers are seated in such a way that no one sits on the allotted seat. The number of such seating arrangements is?

If the constant term in the binomial expansion of $\left(\frac{x^{\frac{3}{2}}}{2}-\frac{4}{x^l}\right)^9$ is $-84$ and the coefficient of $x^{-3 l}$ is $2^\alpha \beta$, where $\beta<0$ is an odd number, then $|\alpha l-\beta|$ is equal to_____

How many electrons are gained by MnO^Θ₄ in strongly alkaline medium?