List of top Questions asked in JEE Main

A point object, 'O' is placed in front of two thin symmetrical coaxial convex lenses L₁ and L₂ with focal length 24 cm and 9 cm respectively. The distance between two lenses is 10 cm and the object is placed 6 cm away from lens L₁ as shown in the figure. The distance between the object and the image formed by the system of two lenses is _____ cm.

A square loop of side 2.0 cm is placed inside a long solenoid that has 50 turns per centimetre and carries as sinusoidally varying current of amplitude 2.5 A and angular frequency 700 rad s^–1. The central axes of the loop and selenoid coincide. The amplitude of the emf induced in the loop is x×10^–4 V . The value of x is ______ . (Take, \(\pi\) = 22/7)

A straight wire carrying of 14 A is bent into a semi-circular arc of radius 2.2 cm as shown in the figure. The magnetic field produced by the current at the centre (O) of the arc is ____ × 10^–4 T.

A rectangular parallelopiped is measured as 1 cm × 1 cm × 100 cm. If its specific resistance is 3 × 10^-7 Ωm, then the resistance between its two opposite rectangular faces will be _____ ×10^-7 Ω.

Match List I with List II:

List I		List II
A	16 g of CH4 (g)	I	Weight 28g
B	1 g of H2 (g)	II	60.2 × 1023 electrons
C	1 mole of N2 (g)	III	Weighs 32 g
D	0.5 mol of SO2 (g)	IV	Occupies 11.4 L volume at STP

Choose the correct answer from the options given below:

The correct relationships between unit cell edge length ‘a’ and radius of sphere ‘r’ for face-centred and body-centred cubic structures respectively are:

Ferric chloride is applied to stop bleeding because-

The correct order of metallic character is:

Gibbs energy vs T plot for the formation of oxides is given below.

For the given diagram, the correct statement is -

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Physical properties of isotopes of hydrogen are different.
Reason R: Mass difference between isotopes of hydrogen is very large.
In the light of the above statements, choose the correct answer from the options given below:

Number of water molecules in washing soda and soda ash respectively are :

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: The energy required to form \(Mg^{2+}\) from Mg is much higher than that required to produce \(Mg^+\)
Reason R: \(Mg^{2+}\) is small ion and carry more charge than \(Mg^{+}\).
In the light of the above statements, choose the correct answer from the options given below.

The correct order of the number of unpaired electrons in the given complexes is
A. \([Fe(CN)_6]^{3–}\)
B. \([FeF_6]^{3–}\)
C. \([CoF_6]^{3–}\)
D. \([Cr(oxalate)_3]^{3–}\)
E. \([Ni(CO)_4]\)
Choose the correct answer from the options given below:

Match List I with List II:

List I - Complex		List II - Crystal Field Splitting energy (△0)
A.	[Ti(H2O)6]2+	I.	– 1.2
B.	[V(H2O)6]2+	II.	– 0.6
C.	[Mn(H2O)6]3+	III.	0
D.	[Fe(H2O)6]3+	IV.	– 0.8

Choose the correct answer from the options given below:

The decreasing order of hydride affinity for following carbocations is:
Choose the correct answer from the options given below:

The major product P formed in the given reaction is:

Incorrect method of preparation for alcohols from the following is:

Buna-S can be represented as:

The reaction used for preparation of soap from fat is :

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: 3.1500 g of hydrated oxalic acid dissolved in water to make 250.0 mL solution will result in 0.1 M oxalic acid solution.
Reason R: Molar mass of hydrated oxalic acid is 126 g mol^–1.
In the light of the above statements, choose the correct answer from the options given below.

The electron in the \(n^{th}\) orbit of \(Li^{2+}\) is excited to \((n + 1)\) orbit using the radiation of energy \(1.47 × 10^{–1}J \) (as shown in the diagrarn). The value of n is ______ .
Given: \(R_H = 2.18 × 10^{–18} J\).

The number of endothermic process/es from the following is _____ .
A. \(I_2 (g) → 2I (g)\)
B. \(HCl (g) → H(g) + Cl (g)\)
C. \(H_2O(l) → H_2O (g)\)
D. \(C(s) + O_2 (g) → CO_2 (g)\)
E. Dissolution of ammonium chloride in water.

An aqueous solution of volume 300 cm³ contains 0.63 g of protein. The osmotic pressure of the solution
at 300 K is 1.29 mbar. The molar mass of the protein is ____ g mol^–1.
Given: R = 0.083 L bar K^–1 mol^–1

\(A(g) ⇋ 2B(g) + C(g)\)
For the given reaction, if the initial pressure is 450 mm Hg and the pressure at time t is 720 mm Hg at a constant temperature T and constant volume V. The fraction of A(g) decomposed under these conditions is \(x × 10^{–1}\). The value of x is _____ . (nearest integer)

The specific conductance of 0.0025 M acetic acid is \(5 × 10^{–5} S\ cm^{–1}\) at a certain temperature. The dissociation constant of acetic acid is ___________ \(× 10^{–7}.\) (Nearest integer) Consider limiting molar conductivity of \(CH_3COOH\) as \(400\  S cm^2 mol^{–1}\).