JEE Main 20 July 2021 Shift 2 Question Paper

Question 1

Consider the line L given by the equation $\frac{x-3}{2}=\frac{y-1}{1}=\frac{z-2}{1}$. Let Q be the mirror image of the point $(2,3,-1)$ with respect to L. Let a plane P be such that it passes through Q, and the line L is perpendicular to P. Then which of the following points is one the plane P ?

Accepted Answer

(A) $(1,2,2)$

Answer

(B) $(-1,1,2)$

Answer

(C) $(1,1,1)$

Answer

(D) $(1,1,2)$

Question 2

If the real part of the complex number $\left(1-\cos	heta+2i\sin	hetaight)^{-1}$ is $\frac{1}{5}$ for $	heta\in(0,\pi)$, then the value of the integral $\int_{0}^{	heta}\sin x\,dx$ is equal to :

Accepted Answer

(D) $1$

Answer

(A) $-1$

Answer

(B) $0$

Answer

(C) $2$

Question 3

The value of $k\in R$, for which the following system of linear equations
$3x-y+4z=3,$
$x+2y-3z=-2,$
$6x+5y+kz=-3,$
has infinitely many solutions, is :

Accepted Answer

(C) $-5$

Answer

(A) $3$

Answer

(B) $-3$

Answer

(D) $5$

Question 4

For the natural numbers $m,n$, if $(1-y)^{m}(1+y)^{n}=1+a_{1}y+a_{2}y^{2}+....+a_{m+n}y^{m+n}$ and $a_{1}=a_{2}=10,$ then the value of $(m+n)$ is equal to :

Accepted Answer

(C) $80$

Answer

(A) $64$

Answer

(B) $88$

Answer

(D) $100$

Question 5

The value of $	an\left(2	an^{-1}\left(\frac{3}{5}ight)+\sin^{-1}\left(\frac{5}{13}ight)ight)$ is equal to :

Accepted Answer

(C) $\frac{220}{21}$

Answer

(A) $\frac{151}{63}$

Answer

(B) $\frac{-291}{76}$

Answer

(D) $\frac{-181}{69}$

Question 6

If $f:R	o R$ is given by $f(x)=x+1,$ then the value of $\lim_{n	o\infty}\frac{1}{n}\left[f(0)+f\left(\frac{5}{n}ight)+f\left(\frac{10}{n}ight)+....+f\left(\frac{5(n-1)}{n}ight)ight]$, is :

Accepted Answer

(C) $\frac{7}{2}$

Answer

(A) $\frac{3}{2}$

Answer

(B) $\frac{1}{2}$

Answer

(D) $\frac{5}{2}$

Question 7

Let P be a variable point on the parabola $y=4x^{2}+1$. Then, the locus of the mid-point of the point P and the foot of the perpendicular drawn from the point P to the line $y=x$ is :

Accepted Answer

(C) $2(3x-y)^{2}+(x-3y)+2=0$

Answer

(A) $2(x-3y)^{2}+(3x-y)+2=0$

Answer

(B) $(3x-y)^{2}+(x-3y)+2=0$

Answer

(D) $(3x-y)^{2}+2(x-3y)+2=0$

Question 8

The sum of all the local minimum values of the twice differentiable function $f:R	o R$ defined by $f(x)=x^{3}-3x^{2}-\frac{3f''(2)}{2}x+f''(1)$ is :

Accepted Answer

(D) $-27$

Answer

(A) $-22$

Answer

(B) $5$

Answer

(C) $0$

Question 9

Let $r_{1}$ and $r_{2}$ be the radii of the largest and smallest circles, respectively, which pass through the point $(-4,1)$ and having their centres on the circumference of the circle $x^{2}+y^{2}+2x+4y-4=0$. If $\frac{r_{1}}{r_{2}}=a+b\sqrt{2},$ then $a+b$ is equal to :

Accepted Answer

(A) $5$

Answer

(B) $11$

Answer

(C) $7$

Answer

(D) $3$

Question 10

If the mean and variance of six observations $7,\ 10,\ 11,\ 15,\ a,\ b$ are $10$ and $\frac{20}{3}$, respectively, then the value of $|a-b|$ is equal to

Accepted Answer

(D) $1$

Answer

(A) $9$

Answer

(B) $7$

Answer

(C) $11$

Question 11

Let $y=y(x)$ satisfies the equation $\frac{dy}{dx}-|A|=0,$ for all $x>0,$ where $A=\begin{bmatrix} y & \sin x & 1 \ 0 & -1 & 1 \ 2 & 0 & \frac{1}{x} \end{bmatrix}$. If $y(\pi)=\pi+2,$ then the value of $y\left(\frac{\pi}{2}ight)$ is :

Accepted Answer

(A) $\frac{\pi}{2}+\frac{4}{\pi}$

Answer

(B) $\frac{3\pi}{2}-\frac{1}{\pi}$

Answer

(C) $\frac{\pi}{2}-\frac{4}{\pi}$

Answer

(D) $\frac{\pi}{2}-\frac{1}{\pi}$

Question 12

Let $f:R-\left\{\frac{\alpha}{6}ight\}	o R$ be defined by $f(x)=\frac{5x+3}{6x-\alpha}$. Then the value of $\alpha$ for which $(fof)(x)=x,$ for all $x\in R-\left\{\frac{\alpha}{6}ight\}$, is :

Accepted Answer

(D) $5$

Answer

(A) $6$

Answer

(B) $8$

Answer

(C) No such $\alpha$ exists

Question 13

The lines $x=ay-1=z-2$ and $x=3y-2=bz-2,\ (ab
eq 0)$ are coplanar, if :

Accepted Answer

(B) $b=1,\ a\in R-\{0\}$

Answer

(A) $a=2,\ b=2$

Answer

(C) $a=2,\ b=3$

Answer

(D) $a=1,\ b\in R-\{0\}$

Question 14

In a triangle ABC, if $\left|\overrightarrow{BC}\right|=3,\left|\overrightarrow{CA}\right|=5$ and $\left|\overrightarrow{BA}\right|=7,$ then the projection of the vector $\overrightarrow{BA}$ on $\overrightarrow{BC}$ is equal to :

Accepted Answer

(D) $\frac{11}{2}$

Answer

(A) $\frac{19}{2}$

Answer

(B) $\frac{13}{2}$

Answer

(C) $\frac{15}{2}$

Question 15

Let $g(t)=\int_{-\pi/2}^{\pi/2}\cos\left(\frac{\pi}{4}t+f(x)\right)dx,$ where $f(x)=\log_{e}\left(x+\sqrt{x^{2}+1}\right),\ x\in R$. Then which one of the following is correct?

Accepted Answer

(D) $\sqrt{2}g(1)=g(0)$

Answer

(A) $g(1)=g(0)$

Answer

(B) $g(1)=\sqrt{2}g(0)$

Answer

(C) $g(1)+g(0)=0$

Question 16

Consider the following three statements :
(A) if 3 + 3 = 7 then 4 + 3 = 8.
(B) If 5 + 3 = 8 then earth is flat.
(C) If both (A) and (B) are true then 5 + 6 = 17.
Then, which of the following statements is correct?

Accepted Answer

(A) (A) and (C) are true while (B) is false

Answer

(B) (A) and (B) are false while (C) is true

Answer

(C) (A) is true while (B) and (C) are false

Answer

(D) (A) is false, but (B) and (C) are true

Question 17

If sum of the first 21 terms of the series $\log_{9^{1/2}}x+\log_{9^{1/3}}x+\log_{9^{1/4}}x+....,$ where $x>0$ is 504, then x is equal to :

Accepted Answer

(D) $81$

Answer

(A) $7$

Answer

(B) $9$

Answer

(C) $243$

Question 18

If [x] denotes the greatest integer less than or equal to x, then the value of the integral $\int_{-\pi/2}^{\pi/2}\left[[x]-\sin x\right]dx$ is equal to :

Accepted Answer

(A) $-\pi$

Answer

(B) $0$

Answer

(C) $1$

Answer

(D) $\pi$

Question 19

Let in a right angled triangle, the smallest angle be $	heta$. If a triangle formed by taking the reciprocal of its sides is also a right angled triangle, then $\sin	heta$ is equal to :

Accepted Answer

(C) $\frac{\sqrt{5}-1}{2}$

Answer

(A) $\frac{\sqrt{2}-1}{2}$

Answer

(B) $\frac{\sqrt{5}+1}{4}$

Answer

(D) $\frac{\sqrt{5}-1}{4}$

Question 20

Let A, B and C be three events such that the probability that exactly one of A and B occurs is $(1-k)$, the probability that exactly one of B and C occurs is $(1-2k)$, the probability that exactly one of C and A occurs is $(1-k)$ and the probability of all A, B and C occur simultaneously is $k^{2}$, where $0<k<1$. Then the probability that at least one of A, B and C occur is :

Accepted Answer

(A) greater than $\frac{1}{2}$

Answer

(B) greater than $\frac{1}{4}$ but less than $\frac{1}{2}$

Answer

(C) exactly equal to $\frac{1}{2}$

Answer

(D) greater than $\frac{1}{8}$ but less than $\frac{1}{4}$

Question 21

Let $\{a_{n}\}_{n=1}^{\infty}$ be a sequence such that $a_{1}=1, a_{2}=1$ and $a_{n+2}=2a_{n+1}+a_{n}$ for all $n\ge 1$. Then the value of $47\sum_{n=1}^{\infty}\frac{a_{n}}{2^{3n}}$ is equal to……..

Accepted Answer

7

Question 22

Consider a triangle having vertices $A(-2,3)$, $B(1,9)$ and $C(3,8)$. If a line L passing through the circum-center of triangle ABC, bisects line BC, and intersects y-axis at point $\left(0,\frac{\alpha}{2}\right)$, then the value of real number $\alpha$ is…………

Accepted Answer

9

Question 23

If the point on the curve $y^{2}=6x$, nearest to the point $\left(3,\frac{3}{2}\right)$ is $(\alpha,\beta)$, then $2(\alpha+\beta)$ is equal to………

Accepted Answer

9

Question 24

Let $A=\{a_{ij}\}$ be a 3 x 3 matrix, where $a_{ij}=\begin{cases}(-1)^{j-i} & 	ext{if } i<j, \ 2 & 	ext{if } i=j, \ (-1)^{i+j} & 	ext{if } i>j,\end{cases}$ then $\det\left(3\,	ext{Adj}\left(2A^{-1}ight)ight)$ is equal to…….

Accepted Answer

108

Question 25

For $p>0$, a vector $\vec{v}_{2}=2\hat{i}+(p+1)\hat{j}$ is obtained by rotating the vector $\vec{v}_{1}=\sqrt{3}\,p\hat{i}+\hat{j}$ by an angle $	heta$ about origin in counter clockwise direction. If $	an	heta=\frac{\left(\alpha\sqrt{3}-2ight)}{\left(4\sqrt{3}+3ight)}$, then the value of $\alpha$ is equal to……….

Accepted Answer

6

Question 26

Let a curve $y=y(x)$ be given by the solution of the differential equation $\cos\left(\frac{1}{2}\cos^{-1}\left(e^{-x}\right)\right)dx=\sqrt{e^{2x}-1}\,dy$
If it intersects y-axis at $y=-1$, and the intersection point of the curve with x-axis is $(\alpha,0)$, then $e^{\alpha}$ is equal to……..

Accepted Answer

2

Question 27

The number of solutions of the equation $\log_{(x+1)}\left(2x^{2}+7x+5\right)+\log_{(2x+5)}(x+1)^{2}-4=0$, $x>0$, is………

Accepted Answer

1

Question 28

Let a function $g:[0,4]	o R$ be defined as $g(x)=\begin{cases}\max\limits_{0\le t\le x}\{t^{3}-6t^{2}+9t-3\}, & 0\le x\le 3 \ 4-x, & 3<x\le 4\end{cases}$, then the number of points in the interval $(0,4)$ where $g(x)$ is NOT differentiable, is…….

Accepted Answer

1

Question 29

For a series LCR circuit with $R = 100\,\Omega$, $L = 0.5\,mH$ and $C = 0.1\,pF$ connected across $220V - 50Hz$ AC supply, the phase angle between current and supplied voltage and the nature of the circuit is :

Accepted Answer

(C) $\approx 90^\circ$, predominantly capacitive circuit

Answer

(A) $\approx 90^\circ$, predominantly inductive circuit

Answer

(B) $0^\circ$, resonance circuit

Answer

(D) $0^\circ$, resistive circuit

Question 30

If the kinetic energy of a moving body becomes four times its initial kinetic energy, then the percentage change in its momentum will be :

Accepted Answer

(A) 100%

Answer

(B) 200%

Answer

(C) 400%

Answer

(D) 300%

Question 31

If time $(t)$, velocity $(\upsilon)$, and angular momentum $(\ell)$ are taken as the fundamental units. Then the dimension of mass $(m)$ in terms of $t, \upsilon,$ and $\ell$ is :

Accepted Answer

(C) $\left[ t^{-1}\,\upsilon^{-2}\,\ell^{1} \right]$

Answer

(A) $\left[ t^{-2}\,\upsilon^{-1}\,\ell^{1} \right]$

Answer

(B) $\left[ t^{-1}\,\upsilon^{1}\,\ell^{-2} \right]$

Answer

(D) $\left[ t^{1}\,\upsilon^{2}\,\ell^{-1} \right]$

Question 32

An electron having de-Broglie wavelength $\lambda$ is indent on a target in a X-ray tube. Cut-off wavelength of emitted X-ray is:

Accepted Answer

(B) $\dfrac{2mc\,\lambda^{2}}{h}$

Answer

(A) 0

Answer

(C) $\dfrac{hc}{mc}$

Answer

(D) $\dfrac{2m^{2}c^{2}\lambda^{2}}{h^{2}}$

Question 33

Two small drops of mercury each of radius R coalesce to from a single large drop. The ratio of total surface energy before and after the change is :

Accepted Answer

(A) $2^{\frac{1}{3}} : 1$

Answer

(B) $1 : 2^{\frac{1}{3}}$

Answer

(C) $2 : 1$

Answer

(D) $1 : 2$

Question 34

Two vectors $\vec{P}$ and $\vec{Q}$ have equal magnitudes. If the magnitude of $\vec{P} + \vec{Q}$ is n times the magnitude of $\vec{P} - \vec{Q}$, then angle between $\vec{P}$ and $\vec{Q}$ is :

Accepted Answer

(B) $\cos^{-1}\left( \dfrac{n^{2}-1}{n^{2}+1} \right)$

Answer

(A) $\sin^{-1}\left( \dfrac{n^{2}-1}{n^{2}+1} \right)$

Answer

(C) $\sin^{-1}\left( \dfrac{n-1}{n+1} \right)$

Answer

(D) $\cos^{-1}\left( \dfrac{n-1}{n+1} \right)$

Question 35

A boy reaches the airport and finds that the escalator is not working. He walks up the stationary escalator in time $t_1$. If he remains stationary on a moving escalator then the escalator takes him up in time $t_2$. The time taken by him to walk up on the moving escalator will be :

Accepted Answer

(A) $\dfrac{t_1 t_2}{t_2 + t_1}$

Answer

(B) $t_2 - t_1$

Answer

(C) $\dfrac{t_1 + t_2}{2}$

Answer

(D) $\dfrac{t_1 t_2}{t_2 - t_1}$

Question 36

The correct relation between the degrees of freedom f and the ratio of specific heat $\gamma$ is :

Accepted Answer

(B) $f = \dfrac{2}{\gamma - 1}$

Answer

(A) $f = \dfrac{2}{\gamma + 1}$

Answer

(C) $f = \dfrac{1}{\gamma + 1}$

Answer

(D) $f = \dfrac{\gamma + 1}{2}$

Question 37

For a certain radioactive process the graph between $\ell n(R)$ and t(sec) is obtained as shown in the figure. Then the value of half life for the unknown radioactive material is approximately :

Accepted Answer

(C) 4.62 sec

Answer

(A) 2.62 sec

Answer

(B) 9.15 sec

Answer

(D) 6.93 sec

Question 38

A body rolls down an inclined plane without slipping. The kinetic energy of rotation is 50% of its translational kinetic energy. The body is :

Accepted Answer

(D) Solid cylinder

Answer

(A) Hollow cylinder

Answer

(B) Ring

Answer

(C) Solid sphere

Question 39

In an electromagnetic wave the electric field vector and magnetic field vector are given as $\vec{E} = E_0 \hat{i}$ and $\vec{B} = B_0 \hat{k}$ respectively. The direction of propagation of electromagnetic wave is along.

Accepted Answer

(C) $\left( -\hat{j} \right)$

Answer

(A) $\left( -\hat{k} \right)$

Answer

(B) $\left( \hat{k} \right)$

Answer

(D) $\hat{j}$

Question 40

The length of a metal wire is $\ell_1$, when the tension in it is $T_1$ and is $\ell_2$ when the tension is $T_2$. The natural length of the wire is :

Accepted Answer

(C) $\dfrac{\ell_1 T_2 - \ell_2 T_1}{T_2 - T_1}$

Answer

(A) $\sqrt{\ell_1 \ell_2}$

Answer

(B) $\dfrac{\ell_1 + \ell_2}{2}$

Answer

(D) $\dfrac{\ell_1 T_2 + \ell_2 T_1}{T_2 + T_1}$

Question 41

A body at rest is moved along a horizontal straight line by a machine delivering a constant power. The distance moved by the body in time 't' is proportional to :

Accepted Answer

(B) $t^{\frac{3}{2}}$

Answer

(A) $t^{\frac{3}{4}}$

Answer

(C) $t^{\frac{1}{2}}$

Answer

(D) $t^{\frac{1}{4}}$

Question 42

Which of the following graphs represent the behaviour of an ideal gas? Symbols have their usual meaning.

Accepted Answer

(C) (C)

Answer

(A) (A)

Answer

(B) (B)

Answer

(D) (D)

Question 43

With what speed should a galaxy move outward with respect to earth so that the sodium $-D$ line at wavelength $5890\,\overset{\circ}{A}$ is observed at $5896\,\overset{\circ}{A}$ ?

Accepted Answer

(C) 306 km / sec

Answer

(A) 322 km / sec

Answer

(B) 296 km / sec

Answer

(D) 336 km / sec

Question 44

A particle is making simple harmonic motion along the X-axis. If at a distances $x_1$ and $x_2$ from the mean position the velocities of the particle are $\upsilon_1$ and $\upsilon_2$ respectively. The time period of its oscillation is given as :

Accepted Answer

(A) $T = 2\pi \sqrt{ \dfrac{x_2^{2} - x_1^{2}}{\upsilon_1^{2} - \upsilon_2^{2}} }$

Answer

(B) $T = 2\pi \sqrt{ \dfrac{x_2^{2} + x_1^{2}}{\upsilon_1^{2} - \upsilon_2^{2}} }$

Answer

(C) $T = 2\pi \sqrt{ \dfrac{x_2^{2} - x_1^{2}}{\upsilon_1^{2} + \upsilon_2^{2}} }$

Answer

(D) $T = 2\pi \sqrt{ \dfrac{x_2^{2} + x_1^{2}}{\upsilon_1^{2} + \upsilon_2^{2}} }$

Question 45

A satellite is launched into a circular orbit of radius R around earth, while a second satellite is launched into a circular orbit of radius 1.02R. The percentage difference in the time periods of the two satellites is :

Accepted Answer

(B) 3.0

Answer

(A) 0.7

Answer

(C) 2.0

Answer

(D) 1.5

Question 46

Consider a binary star system of star A and star B with masses $m_A$ and $m_B$ revolving in a circular orbit of radii $r_A$ and $r_B$, respectively. If $T_A$ and $T_B$ are the time period of star A and star B, respectively, then :

Accepted Answer

(A) $T_A = T_B$

Answer

(B) $T_A > T_B \left( 	ext{if } m_A > m_B ight)$

Answer

(C) $\dfrac{T_A}{T_B} = \left( \dfrac{r_A}{r_B} \right)^{\frac{3}{2}}$

Answer

(D) $T_A > T_B \left( 	ext{if } r_A > r_B ight)$

Question 47

At an angle of $30^{\circ}$ to the magnetic meridian, the apparent dip is $45^{\circ}$. Find the true dip:

Accepted Answer

(A) $	an^{-1}\frac{\sqrt{3}}{2}$

Answer

(B) $	an^{-1}\sqrt{3}$

Answer

(C) $	an^{-1}\frac{1}{\sqrt{3}}$

Answer

(D) $	an^{-1}\frac{2}{\sqrt{3}}$

Question 48

The magnetic susceptibility of a material of a rod is 499. Permeability in vacuum is $4\pi 	imes 10^{-7}\ \mathrm{H/m}$. Absolute permeability of the material of the rod is:

Accepted Answer

(C) $2\pi 	imes 10^{-4}\ \mathrm{H/m}$

Answer

(A) $3\pi 	imes 10^{-4}\ \mathrm{H/m}$

Answer

(B) $\pi 	imes 10^{-4}\ \mathrm{H/m}$

Answer

(D) $4\pi 	imes 10^{-4}\ \mathrm{H/m}$

Question 49

A radioactive substance decays to $\left(\frac{1}{16}\right)^{th}$ of this initial activity in 80 days. The half life of the radioactive substance expressed in days is ____________.

Accepted Answer

20

Question 50

A certain metallic surface is illuminated by monochromatic radiation of wavelength $\lambda$. The stopping potential for photoelectric current for this radiation is $3V_{0}$. If the same surface is illuminated with a radiation of wavelength $2\lambda$, the stopping potential is $V_{0}$. The threshold wavelength of this surface for photoelectric effect is _________ $\lambda$.

Accepted Answer

4

Question 51

Two bodies, a ring and a solid cylinder of same material are rolling down without slipping an inclined plane. The radii of the bodies are same. The ratio of velocity centre of mass at the bottom of the inclined plane of the ring to that of the cylinder is $\frac{\sqrt{x}}{2}$. Then, the value of x is ___________.

Accepted Answer

3

Question 52

A series LCR circuit of $\mathrm{R} = 5\Omega, \mathrm{L} = 20\,\mathrm{mH}$ and $\mathrm{C} = 0.5\,\mu\mathrm{F}$ is connected across an AC supply of 250 V, having variable frequency. The power dissipated at resonance condition is _________ $	imes 10^{2}$ W.

Accepted Answer

125

Question 53

A body rotating with an angular speed of 600 rpm is uniformly accelerated to 1800 rpm in 10 sec. The number of rotations made in the process is ____________.

Accepted Answer

200

Question 54

For the forward biased diode characteristics shown in the figure, the dynamic resistance at $\mathrm{I}_{\mathrm{D}} = 3\,\mathrm{mA}$ will be ___________ $\Omega$.

Accepted Answer

25

Question 55

One mole of an ideal gas at $27^{\circ}\mathrm{C}$ is taken from A to B as shown in the given PV indicator diagram. The work done by the system will be ________ $	imes 10^{-1}$ J. [Given : $\mathrm{R} = 8.3\,\mathrm{J/mole\ K}$, $\ell\mathrm{n}\,2 = 0.6931$ ] (Round off to the nearest integer)

Accepted Answer

17258

Question 56

In the given figure switches $\mathrm{S}_{1}$ and $\mathrm{S}_{2}$ are in open condition. The resistance across ab when the switches $\mathrm{S}_{1}$ and $\mathrm{S}_{2}$ are closed is ________ $\Omega$.

Accepted Answer

10

Question 57

A body of mass 'm' is launched up on a rough inclined plane making an angle of $30^{\circ}$ with the horizontal. The coefficient of friction between the body and plane is $\frac{\sqrt{x}}{5}$ if the time of ascent is half of the time of descent. The value of x is ___________.

Accepted Answer

3

Question 58

A zener diode having zener voltage 8 V and power dissipation rating of 0.5 W is connected across a potential divider arranged with maximum potential drop across zener diode is as shown in the diagram. The value of protective resistance $\mathrm{R}_{\mathrm{p}}$ is __________ $\Omega$.

Accepted Answer

192

Question 59

Major product P of above reaction, is :

Accepted Answer

(D) (D)

Answer

(A) (A)

Answer

(B) (B)

Answer

(C) (C)

Question 60

Outermost electronic configuration of a group 13 element, E, is $\mathrm{4s^2, 4p^1}$. The electronic configuration of an element of p-block period-five placed diagonally to element, E is:

Accepted Answer

(A) $\mathrm{[Kr]4d^{10}\,5s^2\,5p^2}$

Answer

(B) $\mathrm{[Kr]3d^{10}\,4s^2\,4p^2}$

Answer

(C) $\mathrm{[Xe]5d^{10}\,6s^2\,6p^2}$

Answer

(D) $\mathrm{[Ar]3d^{10}\,4s^2\,4p^2}$

Question 61

In the above reactions, product A and product B respectively are:

Accepted Answer

(B) (B)

Answer

(A) (A)

Answer

(C) (C)

Answer

(D) (D)

Question 62

Bakelite is a cross- linked polymer of formaldehyde and :

Accepted Answer

(C) Novolac

Answer

(A) PHBV

Answer

(B) Buna – S

Answer

(D) Dacron

Question 63

Consider two chemical reactions (A) and (B) that take place during metallurgical process:
(a) $\mathrm{ZnCO_{3(s)} \xrightarrow{\Delta} ZnO_{(s)} + CO_{2(g)}}$
(b) $\mathrm{2ZnS_{(s)} + 3O_{2(g)} \xrightarrow{\Delta} 2ZnO_{(s)} + 2SO_{2(g)}}$
The correct option of names given to them respectively is :

Accepted Answer

(A) (a) is calcination and (b) is roasting

Answer

(B) Both (a) and (b) are producing same product so both are calcination

Answer

(C) Both (a) and (b) are producing same product so both are roasting

Answer

(D) (a) is roasting and (b) is calcination

Question 64

The correct order of their reactivity towards hydrolysis at room temperature is:

Accepted Answer

(D) (a) > (b) > (c) > (d)

Answer

(A) (d) > (b) > (a) > (c)

Answer

(B) (d) > (a) > (b) > (c)

Answer

(C) (a) > (c) > (b) > (d)

JEE Main 20 July 2021 Shift 2 Question Paper with Answers

Physics — JEE Main 20 July 2021 Shift 2

Chemistry — JEE Main 20 July 2021 Shift 2

Mathematics — JEE Main 20 July 2021 Shift 2

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