JEE Main 2021 · 24 Feb 2021 · Shift 2

Q1.On the basis of kinetic theory of gases, the gas exerts pressure because its molecules:

Q2.Figure shows a circuit that contains four identical resistors with resistance $\mathrm{R}=2.0\Omega$, two identical inductors with inductance $\mathrm{L}=2.0\mathrm{mH}$ and an ideal battery with emf $\mathrm{E}=9\mathrm{V}$. The current ' i ' just after switch ' $S$ ' is clo …

Q3.The period of oscillation of a simple pendulum is $T=2\pi \sqrt{\frac{L}{g}}$. Measured value of ' $L$ ' is 1.0 m from meter scale having a minimum division of 1 mm and time of one- complete oscillation is 1.95 s measured from stopwatch of 0.01 s resolution. The percentage error …

Q4.Zener breakdown occurs in a $\mathrm{P}-\mathrm{n}$ junction having P and n both:

Q5.A body weighs 49 N on a spring balance at the north pole. What will be its weight recorded on the same weighing machine, if it is shifted to the equator?
[ use $\mathrm{g}=\frac{\mathrm{Gm}}{{\mathrm{R}}^2}=9.8{\mathrm{ms}}^{-2}$ and radius of earth, …

Q6.A soft ferromagnetic material is placed in an external magnetic field. The magnetic domains:

Q7.Given below are two statements:
Statement I: PN junction diodes can be used to function as transistor simply by connecting two diodes, back to back, which acts as the base terminal.
Statement II: In the study of transistor, the amplification factor β indicates ratio of the collec …

Q8.A particle is projected with velocity ${\mathrm{v}}_0$ along x -axis. A damping force is acting on the particle which is proportional to the square of the distance from the origin i.e. $\mathrm{ma}=-\alpha {\mathrm{x}}^2$. The distance at which the particle stops:

Q9.Two electrons each are fixed at a distance ' $2d$ '. A third charge proton placed at the midpoint is displaced slightly by a distance $x(x\ll d)$ perpendicular to the line joining the two fixed charges. Proton will execute simple harmonic motion having angular frequency:
(m = m …

Q10.According to Bohr atom model, in which of the following transitions will the frequency be maximum ?

Q11.In the given figure, a body of mass M is held between two massless springs, on a smooth inclined plane. The free ends of the springs are attached to firm supports. If each spring has spring constant k, the frequency of oscillation of given body is:

Q12.An X - ray tube is operated at 1.24 million volt. The shortest wavelength of the produced photon will be:

Q13.When a particle executes SHM, the nature of graphical representation of velocity as a function of displacement is:

Q14.If one mole of an ideal gas at ( $P_1{V}_1$ ) is allowed to expand reversibly and isothermally ( A to B ) its pressure is reduced to one- half of the original pressure (see figure). This is followed by a constant volume cooling till its pressure is reduced to one-fourth of the …

Q15.Match List - I with List -II

List - I
(a) Source of microwave frequency
(b) Source of infrared frequency
(c) Source of Gamma Rays
(d) Source of X- rays

List - II
(i) Radioactive decay of nucleus
(ii) Magnetron
(iii) Inner shell electrons
(iv) Vibration of atoms and molecules
(v …

Q16.If the source of light used in a Young's double slit experiment is changed from red to violet:

Q17.The logic circuit shown above is equivalent to:

Q18.The de Broglie wavelength of a proton and $\alpha$- particle are equal. The ratio of their velocities is:

Q19.Which of the following equations represents a traveling wave?

Q20.A circular hole of radius $\left(\frac{a}{2}\right)$ is cut of a circular disc of radius 'a' as shown in figure. The centroid of the remaining circular portion with respect to point 'O' will be:

Q21.The root mean square speed of molecules of a given mass of a gas at $27^{\circ }\mathrm{C}$ and 1 atmosphere pressure is $200{\mathrm{ms}}^{-1}$. The root mean square speed of molecules of the gas at $127^{\circ }\mathrm{C}$ and 2 atmosphere pressure is …

Q22.A point charge of $+12\mu \mathrm{C}$ is at a distance 6 cm vertically above the centre of a squared of side 12 cm as shown in figure. The magnitude of the electric flux through the square will be........... $\times 10^3{\mathrm{Nm}}^2/\mathrm{C}$.

Q23.A uniform thin bar of mass 6 kg and length 2.4 meter is bent to make an equilateral hexagon. The moment of inertia about an axis passing through the centre of mass and perpendicular to the plane of hexagon is ____ $\times 10^{-1}\mathrm{kg}{\mathrm{m}}^2$.

Q24.A uniform metallic wire is elongated by 0.04 m when subjected to a linear force $F$. The elongation, if its length and diameter is doubled and subjected to the same force will be ____ cm.

Q25.A series LCR circuit is designed to resonate at an angular frequency ${\omega }_0=10^5\mathrm{rad}/\mathrm{s}$. The circuit draws 16 W power from 120 V source at resonance. The value of resistance ' R ' in the circuit is
____ $\Omega$.

Q26.A signal of 0.1 kW is transmitted in a cable. The attenuation of cable is -5 dB per km and cable length is 20 km . The power received at receiver is $10^{-x}\mathrm{W}$. The value of x is ____
[ Given in dB …

Q27.An electromagnetic wave of frequency 3 GHz enters a dielectric medium of relative electric permittivity 2.25 from vacuum. The wavelength of this wave in that medium will be ____ $\times 10^{-2}\mathrm{cm}$.

Q28.A cylindrical wire of radius 0.5 mm and conductivity $5\times 10^7\mathrm{S}/\mathrm{m}$ is subjected to an electric field of $10\mathrm{mV}/\mathrm{m}$. The expected value of current in the wire will be $x^3\pi \mathrm{mA}$. The value of $x$ is
____

Q29.Two cars are approaching each other at an equal speed of $7.2\mathrm{km}/\mathrm{hr}$. When they see each other, both blow horns of 676 Hz . The beat frequency heard by each driver will be ____ Hz . [Velocity of sound in air is $340\mathrm{m}/\mathrm{s}$ ]

Q30.Two solids $A$ and $B$ of mass 1 kg and 2 kg respectively are moving with equal linear momentum. The ratio of their kinetic energies $(\text{ K.E }{)}_A:(\text{ K.E }{)}_B$ will be $\frac{A}{1}$, so the value of $A$ will be ______

Q1.What is the correct order of the following elements with respect to their density?

Q2.Match List - I and list - II.

List - I
(a) Valium
(b) Morphine
(c) Norethindrone
(d) Vitamin ${\mathrm{B}}_{12}$

List - II
(i) Antifertility drug
(ii) Pernicious anaemia
(iii) Analgesic
(iv) Tranquilizer

Q3.Most suitable salt which can be used for efficient clotting of blood will be:

Q4.Match List - I with List - II

List - I
(Metal)
(a) Aluminium
(b) Iron
(c) Copper
(d) Zinc

List - II
(Ores)
(i) Siderite
(ii) Calamine
(iii) Kaolinite
(iv) Malachite

Choose the correct answer from the options given below:

Q5.Match List - I and List - II

List - I
(a) (see structure)
(b) (see structure)
(c) (see structure)
(d) (see structure)

List - II
(i) ${\mathrm{Br}}_2/\mathrm{NaOH}$
(ii) ${\mathrm{H}}_2/\mathrm{Pd}-{\mathrm{BaSO}}_4$
(iii) $\mathrm{Zn}(\mathrm{Hg})/$ Conc. HCl
(iv) …

Q6.The incorrect statement among the following is:

Q7.Which one of the following compounds is non-aromatic?

Q8.Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : Hydrogen is the most abundant element in the Universe, but it is not the most abundant gas in the troposphere.
Reason R: Hydrogen is the lightest element
In the li …

Q9.The correct set from the following in which both pairs are in correct order of melting point is :

Q10.The calculated magnetic moments (spin only value) for species ${\left[{\mathrm{FeCl}}_4\right]}^{2-}$, ${\left[\mathrm{Co}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_3\right]}^{3-}$ and ${\mathrm{MnO}}_4^{2-}$ respectively are:

Q11.Which one of the following carbonyl compound cannot be prepared by addition of water on an alkyne in the presence of ${\mathrm{HgSO}}_4$ and ${\mathrm{H}}_2{\mathrm{SO}}_4$ ?

Q12.In polymer Buna - S: 'S' stands for:

Q13.What is the correct sequence of reagents used for converting nitrobenzene into mdibromobenzene?

Q14.The diazonium salt of which of the following compounds will form a coloured dye on reaction with $\beta$- Naphthol in NaOH ?

Q15.Given below are two statements:
Statement I: The value of the parameter " Biochemical Oxygen Demand (BOD)' is important for survival of aquatic life.
Statement II : The optimum value of BOD is 6.5 ppm .
In the light of the above statements, choose the most appropriate answer from …

Q16.The correct order of the following compounds showing increasing tendency towards nucleophilic substitution reaction is:
(i) (see structure)
(ii) (see structure)
(iii) (see structure)
(iv) (see structure)

Q17.According to Bohr's atomic theory:
(A) Kinetic energy of electron is $\propto \frac{z^2}{n^2}$
(B) The product of velocity ( v ) of electron and principal quantum number ( n ) ' vn ' $\propto {\mathrm{Z}}^2$
(C) Frequency of revolution of electron in an orbit is …

Q18.Match List - I with List - II

List - I (salt)
(a) LiCl
(b) NaCl
(c) RbCl
(d) CsCl

List - II (Flame colour wavelength)
(i) 455.5 nm
(ii) 670.8 nm
(iii) 780.0 nm
(iv) 589.2 nm

Choose the correct answer from the options given below:

Q19.The correct shape and $\mathrm{I}-\mathrm{I}-\mathrm{I}$ bond angles respectively in ${\mathrm{I}}_3^{-}$ion are:

Q20.Which of the following reagent is suitable for the preparation of the product in the above reaction?

Q21.The total number of amines among the following which can be synthesized by Gabriel synthesis is.
(A) (see structure)
(B) (see structure)
(C) (see structure)
(D) (see structure)

Q22.Sucrose hydrolyses in acid solution into glucose and fructose following first order rate law with a half- life of 3.33 h at $25^{\circ }\mathrm{C}$. After 9 h , the fraction of sucrose remaining is f . The value of ${\log }_{10}\left(\frac{1}{\mathrm{f}}\right)$ is $\_\_\_\_$ …

Q23.The solubility product of ${\mathrm{PbI}}_2$ is $8.0\times 10^{-9}$. The solubility of lead iodide in 0.1 molar solution of lead nitrate is $x\times 10^{-6}\mathrm{mol}/\mathrm{L}$. The value of x is $\_\_\_\_$ (Rounded off to the nearest integer) [Given $\sqrt{2}=1.41$ ]

Q24.The formula of a gaseous hydrocarbon which requires 6 times of its own volume of ${\mathrm{O}}_2$ for complete oxidation and produces 4 times its own volume of ${\mathrm{CO}}_2$ is ${\mathrm{C}}_{\mathrm{x}}{\mathrm{H}}_{\mathrm{y}}$. The value of y is

Q25.1.86 g of aniline completely reacts to form acetanilide. 10% of the product is lost during purification. Amount of acetanilide obtained after purification (in g) is $\_\_\_\_$ $\times 10^{-2}$.

Q26.The volume occupied by 4.75 g of acetylene gas at $50^{\circ }\mathrm{C}$ and 740 mmHg pressure is $\_\_\_\_$ L
(Rounded off to the nearest integer)
[Given $\mathrm{R}=0.0826\mathrm{L}\mathrm{atm}{\mathrm{K}}^{-1}{\mathrm{mol}}^{-1}$]

Q27.The magnitude of the change in oxidising power of the ${\mathrm{MnO}}_4^{-}/{\mathrm{Mn}}^{2+}$ couple is $\mathrm{x}\times 10^{-4}\mathrm{V}$, if the ${\mathrm{H}}^{+}$ concentration is decreased from 1 M to $10^{-4}\mathrm{M}$ at $25^{\circ }\mathrm{C}$ (Assume concentration o …

Q28.Assuming ideal behaviour, the magnitude of $\log \mathrm{K}$ for the following reaction at $25^{\circ }\mathrm{C}$ is $x\times 10^{-1}$. The value of $x$ is $\_\_\_\_$ (integer answer) …

Q29.${\mathrm{C}}_6{\mathrm{H}}_6$ freezes at $5.5^{\circ }\mathrm{C}$. The temperature at which a solution of 10 g of ${\mathrm{C}}_4{\mathrm{H}}_{10}$ in 200 g of ${\mathrm{C}}_6{\mathrm{H}}_6$ freeze is $\_\_\_\_$ ${}^{\circ }\mathrm{C}$ (The molal freezing point depression cons …

Q30.Among the following allotropic forms of sulphur, the number of allotropic forms, which will show paramagnetism is $\_\_\_\_$
(A) $\alpha$ - sulphur
(B) $\beta$ - sulphur
(C) ${\mathrm{S}}_2$ - form

Q1.Let $\mathrm{f}(\mathrm{x})$ be a differentiable function defined on $[0,2]$ such that $f^{\prime }(x)=f^{\prime }(2-x)$ for all $\mathrm{x}\in (0,2)$, $f(0)=1$ and $f(2)=e^2$. Then the value of ${\int }_0^{2}f(x)dx$ is

Q2.The value of the integral ${\int }_1^3\left[x^2-2x-2\right]dx$, where $[x]$ denotes the greatest integer less than or equal to $x$, is

Q3.For the system of linear equations:
$x-2y=1,x-y+kz=-2,ky+4z=6,k\in R$,
Consider the following statements:
(A) The system has unique solution if $\mathrm{k}\ne 2,\mathrm{k}\ne -2$.
(B) The system has unique solution if $\mathrm{k}=-2$.
(C) The system has unique solutio …

Q4.Let $\mathrm{a},\mathrm{b}\in \mathrm{R}$. If the mirror image of the point $\mathrm{P}(\mathrm{a},6,9)$ with respect to the line $\frac{x-3}{7}=\frac{y-2}{5}=\frac{z-1}{-9}$ is
$(20,\mathrm{b},-\mathrm{a}-9)$, then $|\mathrm{a}+\mathrm{b}|$ is equal to:

Q5.Let $\mathrm{a},\mathrm{b},\mathrm{c}$ be in arithmetic progression. Let the centroid of the triangle with vertices $(\mathrm{a},\mathrm{c}),(2,\mathrm{b})$ and $(a,b)$ be $\left(\frac{10}{3},\frac{7}{3}\right)$. If $\alpha ,\beta$ are the roots of the equation …

Q6.Let $f:R\to R$ be defined as
$f(x)=\{\begin{array}{ll}-55x,& \text{ if }x<-5\\ 2x^3-3x^2-120x,& \text{ if }-5\le x\le 4\\ 2x^3-3x^2-36x-336,& \text{ if }x>4,\end{array}$
Let $A=\{x\in R:f$ is increasing $\}$. Then $A$ is equal to:

Q7.The probability that two randomly selected subsets of the set $\{1,2,3,4,5\}$ have exactly two elements in their intersection is:

Q8.The area of the region : $R=\left\{(x,y):5x^2\le y\le 2x^2+9\right\}$ is:

Q9.Let $A$ and $B$ are $3\times 3$ real matrices such that $A$ is symmetric matrix and $B$ is skew- symmetric matrix. Then the system of linear equations $\left(A^2{B}^2-B^2{A}^2\right)X=O$, where $X$ is a $3\times 1$ column matrix of unknown variables and $O$ is a …

Q10.For which of the following curves, the line $x+\sqrt{3y}=2\sqrt{3}$ is the tangent at the point $\left(\frac{3\sqrt{3}}{2},\frac{1}{2}\right)$ ?

Q11.If $\mathrm{n}\ge 2$ is a positive integer, then the sum of the series ${}^{\mathrm{n}+1}{\mathrm{C}}_2+2\left({}^2{\mathrm{C}}_2+{}^3{\mathrm{C}}_2+{}^4{\mathrm{C}}_2+\dots +{}^{\mathrm{n}}{\mathrm{C}}_2\right)$ is:

Q12.The vector equation of the plane passing through the intersection of the planes $\vec{r}\cdot (\hat{i}+\hat{j}+\hat{k})=1$ and $\vec{r}\cdot (\hat{i}-2\hat{j})=-2$, and the point $(1,0,2)$ is:

Q13.The negation of the statement $\sim p\wedge (p\vee q)$ is:

Q14.Let $f$ be a twice differentiable function defined on $R$ such that $f(0)=1,f^{\prime }(0)=2$ and $f(x)\ne 0$ for all $x\in R$. If $\left|\begin{array}{ll}f(x)& f^{\prime }(x)\\ f^{\prime }(x)& f^{\prime \prime }(x)\end{array}\right|=0$, for all $x\in R$, then the value of …

Q15.If $P$ is a point on the parabola $y=x^2+4$ which is closest to the straight line $y=4x-1$, then the co-ordination of $P$ are:

Q16.A possible value of $\tan \left(\frac{1}{4}{\sin }^{-1}\frac{\sqrt{63}}{8}\right)$ is:

Q17.For the statements $p$ and $q$, consider the following compound statements:
(a) $(\sim q\wedge (p\to q))\to \sim p$
(b) $((p\vee q)\wedge \sim p)\to q$

Then which of the following statements is correct?

Q18.If the curve $y=a{x}^2+bx+c,x\in R$ passes through the point $(1,2)$ and the tangent line to this curve at origin is $y=x$, then the possible values of $a,b,c$ are:

Q19.The angle of elevation of a jet plane from a point A on the ground is $60^{\circ }$. After a flight of 20 seconds at the speed of 432 km / hour, the angle of elevation changes to $30^{\circ }$. If the jet plane is flying at a constant height, then its height is:

Q20.If a curve $y=f(x)$ passes through the point $(1,2)$ and satisfies $x\frac{dy}{dx}+y=b{x}^4$, then for what value of $b,{\int }_1^{2}f(x)dx=\frac{62}{5}$ ?

Q21.Let $\lambda$ be an integer. If the shortest distance between the lines $x-\lambda =2y-1=-2z$ and $x=y+2\lambda =z-\lambda$ is $\frac{\sqrt{7}}{2\sqrt{2}}$, then the value of $|\lambda |$ is

Q22.For integers $n$ and $r$, let $\left(\genfrac{}{}{0ex}{}{n}{r}\right)=\{\begin{array}{ll}n{C}_r,& \text{ if }n\ge r\ge 0\\ 0,& \text{ otherwise }\end{array}$
The maximum value of k for which the sum …

Q23.Let $\mathrm{i}=\sqrt{-1}$. If $\frac{(-1+\mathrm{i}\sqrt{3}{)}^{21}}{(1-\mathrm{i}{)}^{24}}+\frac{(1+\mathrm{i}\sqrt{3}{)}^{21}}{(1+\mathrm{i}{)}^{24}}=\mathrm{k}$, and $\mathrm{n}=[|\mathrm{k}|]$ be the greatest integral part of $|\mathrm{k}|$. Then …

Q24.The number of the real roots of the equation $(x+1{)}^2+|x-5|=\frac{27}{4}$ is

Q25.Let a point $P$ be such that its distance from the point $(5,0)$ is thrice the distance of $P$ from the point $(-5,0)$. If the locus of the point $P$ is a circle of radius $r$, then $4r^2$ is equal to ____

Q26.The sum of first four terms of a geometric progression (G.P) is $\frac{65}{12}$ and the sum of their respective reciprocals is $\frac{65}{18}$. If the product of first three terms of the G.P is 1, and the third term is $\alpha$, then $2\alpha$ is ____

Q27.The students ${\mathrm{S}}_1,{\mathrm{S}}_2,\dots \dots .{\mathrm{S}}_{10}$ are to be divided into 3 groups $\mathrm{A},\mathrm{B}$ and C such that each group has at least one student and the group C has at most 3 students. Then the total number of possibilities of formi …

Q28.If $a+\alpha =1,b+\beta =2$ and $af(x)+\alpha f\left(\frac{1}{x}\right)=bx+\frac{\beta }{x},x\ne 0$, then the value of the equation $\frac{f(x)+f\left(\frac{1}{x}\right)}{x+\frac{1}{x}}$ is. ____

Q29.If the variance of 10 natural numbers $1,1,1\dots \dots 1,\mathrm{k}$ less than 10, then the maximum possible value of $k$ is ____

Q30.If the area of the triangle formed by the positive $x$-axis, the normal and the tangent to the circle $(x-2{)}^2+(y-3{)}^2=25$ at the point $(5,7)$ is $A$, then $24A$ is equal to ____