List of top Questions asked in JEE Main- 2021

Match List - I with List - II :

	List - I		List - II
(a)	\([\mathrm{Co(NH_3)_6}][\mathrm{Cr(CN)_6}]\)	(i)	Linkage isomerism
(b)	\([\mathrm{Co(NH_3)_3(NO_2)_3}]\)	(ii)	Solvate isomerism
(c)	\([\mathrm{Cr(H_2O)_6}]\mathrm{Cl_3}\)	(iii)	Co-ordination isomerism
(d)	\(cis-[\mathrm{CrCl_2(ox)_2}]^{3-}\)	(iv)	Optical isomerism

Choose the correct answer from the options given below :

The correct pair(s) of the ambident nucleophiles is(are)
(A) \(\mathrm{AgCN/KCN}\)
(B) \(\mathrm{RCOOAg/RCOOK}\)
(C) \(\mathrm{AgNO_2/KNO_2}\)
(D) \(\mathrm{AgI/KI}\)

Given below are two statements :
Statement I : 2-methylbutane on oxidation with \(\mathrm{KMnO_4}\) gives 2-methylbutan-2-ol.
Statement II : n-alkanes can be easily oxidised to corresponding alcohols with \(\mathrm{KMnO_4}\).
Choose the correct option :

During which of the following processes, does entropy decrease?
(A) Freezing of water to ice at \(0^\circ\mathrm{C}\)
(B) Freezing of water to ice at \(-10^\circ\mathrm{C}\)
(C) \(\mathrm{N_2(g)+3H_2(g)\to2NH_3(g)}\)
(D) Adsorption of CO(g) on lead surface.
(E) Dissolution of NaCl in water
Choose the correct answer from the options given below :

In the above reaction, the structural formula of (A), "X" and "Y" respectively are :

Primary, secondary and tertiary amines can be separated using:

Choose the correct statement regarding the formation of carbocations A and B given.

Nitrogen can be estimated by Kjeldahl's method for which of the following compound?

A body of mass 1 kg rests on a horizontal floor with which it has a coefficient of static friction \(\frac{1}{\sqrt{3}}\). It is desired to make the body move by applying the minimum possible force F N. The value of F will be ____________. (Round off to the Nearest Integer) [Take g = 10 \(\mathrm{ms^{-2}}\) ]

Amongst the following, the linear species is :

\(\mathrm{C_{12}H_{22}O_{11}+H_2O\ \xrightarrow{\text{Enzyme A}}\ \underset{\text{Glucose}}{C_6H_{12}O_6}+\underset{\text{Fructose}}{C_6H_{12}O_6}}\)
\(\mathrm{\underset{\text{Glucose}}{C_6H_{12}O_6}\ \xrightarrow{\text{Enzyme B}}\ 2C_2H_5OH+2CO_2}\)
In the above reactions, the enzyme A and enzyme B respectively are :

A boy of mass 4 kg is standing on a piece of wood having mass 5 kg. If the coefficient of friction between the wood and the floor is 0.5, the maximum force that the boy can exert on the rope so that the piece of wood does not move from its place is __________ N. (Round off to the Nearest Integer) [Take g = 10 \(\mathrm{ms^{-2}}\) ]

The image of an object placed in air formed by a convex refracting surface is at a distance of 10 m behind the surface. The image is real and is at \(\frac{2^{rd}}{3}\) of the distance of the object from the surface. The wavelength of light inside the surface is \(\frac{2}{3}\) times the wavelength in air. The radius of the curved surface is \(\frac{x}{13}\) m. The value of 'x' is ____________.

A 2\(\mu\)F capacitor C₁ is first charged to a potential difference of 10V using a battery. Then the battery is removed and the capacitor is connected to an uncharged capacitor C₂ of 8 \(\mu\)F. The charge in C₂ on equilibrium condition is ____________ \(\mu\)C. (Round off to the Nearest Integer)

Suppose you have taken a dilute solution of oleic acid in such a way that its concentration becomes 0.01 cm³ of oleic acid per cm³ of the solution. Then you make a thin film of this solution (monomolecular thickness) of area 4 cm² by considering 100 spherical drops of radius \(\left(\frac{3}{40\pi}\right)^{\frac{1}{3}}\times 10^{-3}\) cm. Then the thickness of oleic acid layer will be \(x\times 10^{-14}\) m. Where x is ____________.

The disc of mass M with uniform surface mass density \(\sigma\) is shown in the figure. The centre of mass of the quarter disc (the shaded area) is at the position \(\frac{xa}{3\pi},\ \frac{xa}{3\pi}\) where x is ____________. (Round off to the Nearest Integer).
[a is an area as shown in the figure]

A carrier signal C(t) = 25 sin(2.512 × 10¹⁰t) is amplitude modulated by a message signal m(t) = 5 sin(1.57 × 10⁸t) and transmitted through an antenna. What will be the bandwidth of the modulated signal?

The electric field intensity produced by the radiation coming from a 100 W bulb at a distance of 3 m is E. The electric field intensity produced by the radiation coming from 60W at the same distance is \(\sqrt{\frac{x}{5}}\) E. Where the value of x = ____________.

A block of mass 1 kg attached to a spring is made to oscillate with an initial amplitude of 12 cm. After 2 minutes the amplitude decreases to 6 cm. Determine the value of the damping constant for this motion . (take ln 2 = 0.693)

Which one is the correct option for the two different thermodynamic processes?

Two identical blocks A and B each of mass m resting on the smooth horizontal floor are connected by a light spring of natural length L and spring constant K. A third block C of mass m moving with a speed v along the line joining A and B collides with A. The maximum compression in the spring is

An object is located at 2 km beneath the surface of the water. If the fractional compression \(\frac{\Delta V}{V}\) is 1.36%, the ratio of hydraulic stress to the corresponding hydraulic strain will be ____________. [Given : density of water is 1000 kgm^-3 and g = 9.8 ms^-2]

A geostationary satellite is orbiting around an arbitrary planet 'P' at a height of 11R above the surface of 'P', R being the radius of 'P'. The time period of another satellite in hours at a height of 2R from the surface of 'P' is _________. 'P' has the time period of 24 hours.

The four arms of a Wheatstone bridge have resistances as shown in the figure. A galvanometer of \(15\ \Omega\) resistance is connected across BD. Calculate the current through the galvanometer when a potential difference of 10V is maintained across AC.

A rubber ball is released from a height of 5 m above the floor. It bounces back repeatedly, always rising to \(\frac{81}{100}\) of the height through which it falls. Find the average speed of the ball. (Take g = 10 ms^-2)