JEE Main 25 February 2021 Shift 1 Question Paper

Question 1

The coefficients a, b and c of the quadratic equation, $ax^{2} + bx + c = 0$ are obtained by throwing a dice three times. The probability that this equation has equal roots is :

Accepted Answer

(D) $\frac{5}{216}$

Answer

(A) $\frac{1}{54}$

Answer

(B) $\frac{1}{72}$

Answer

(C) $\frac{1}{36}$

Question 2

Let $\alpha$ be the angle between the lines whose direction cosines satisfy the equations $l + m - n = 0$ and $l^{2} + m^{2} - n^{2} = 0$. Then the value of $\sin^{4}\alpha + \cos^{4}\alpha$ is :

Accepted Answer

(C) $\frac{5}{8}$

Answer

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

Answer

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

Answer

(D) $\frac{3}{8}$

Question 3

The value of the integral $\int \frac{\sin	heta \cdot \sin 2	heta (\sin^{6}	heta + \sin^{4}	heta + \sin^{2}	heta)\sqrt{2\sin^{4}	heta + 3\sin^{2}	heta + 6}}{1 - \cos 2	heta}\, d	heta$ is (where c is a constant of integration)

Accepted Answer

(C) $\frac{1}{18}\left[11 - 18\cos^{2}	heta + 9\cos^{4}	heta - 2\cos^{6}	hetaight]^{\frac{3}{2}} + c$

Answer

(A) $\frac{1}{18}\left[9 - 2\sin^{6}	heta - 3\sin^{4}	heta - 6\sin^{2}	hetaight]^{\frac{3}{2}} + c$

Answer

(B) $\frac{1}{18}\left[11 - 18\sin^{2}	heta + 9\sin^{4}	heta - 2\sin^{6}	hetaight]^{\frac{3}{2}} + c$

Answer

(D) $\frac{1}{18}\left[9 - 2\cos^{6}	heta - 3\cos^{4}	heta - 6\cos^{2}	hetaight]^{\frac{3}{2}} + c$

Question 4

A man is observing, from the top of a tower, a boat speeding towards the tower from a certain point A, with uniform speed. At that point, angle of depression of the boat with the man's eye is $30^{\circ}$ (Ignore man's height). After sailing for 20 seconds towards the base of the tower (which is at the level of water), the boat has reached a point B, where the angle of depression is $45^{\circ}$. Then the time taken (in seconds) by the boat from B to reach the base of the tower is :

Accepted Answer

(D) $10(\sqrt{3} + 1)$

Answer

(A) $10(\sqrt{3} - 1)$

Answer

(B) $10\sqrt{3}$

Answer

(C) $10$

Question 5

If $0 < 	heta, \phi < \frac{\pi}{2}$, $x = \sum_{n=0}^{\infty} \cos^{2n}	heta$, $y = \sum_{n=0}^{\infty} \sin^{2n}\phi$ and $z = \sum_{n=0}^{\infty} \cos^{2n}	heta \cdot \sin^{2n}\phi$ then :

Accepted Answer

(D) $xy + z = (x + y)z$

Answer

(A) $xyz = 4$

Answer

(B) $xy - z = (x + y)z$

Answer

(C) $xy + yz + zx = z$

Question 6

The equation of the line through the point (0, 1, 2) and perpendicular to the line $\frac{x-1}{2} = \frac{y+1}{3} = \frac{z-1}{-2}$ is :

Accepted Answer

(A) $\frac{x}{-3} = \frac{y-1}{4} = \frac{z-2}{3}$

Answer

(B) $\frac{x}{3} = \frac{y-1}{4} = \frac{z-2}{3}$

Answer

(C) $\frac{x}{3} = \frac{y-1}{-4} = \frac{z-2}{3}$

Answer

(D) $\frac{x}{3} = \frac{y-1}{4} = \frac{z-2}{-3}$

Question 7

The statement $A \rightarrow (B \rightarrow A)$ is equivalent to:

Accepted Answer

(B) $A \rightarrow (A \vee B)$

Answer

(A) $A \rightarrow (A \wedge B)$

Answer

(C) $A \rightarrow (A \rightarrow B)$

Answer

(D) $A \rightarrow (A \leftrightarrow B)$

Question 8

The integer 'k', for which the inequality $x^{2} - 2(3k - 1)x + 8k^{2} - 7 > 0$ is valid for every x in R is :

Accepted Answer

(A) $3$

Answer

(B) $2$

Answer

(C) $4$

Answer

(D) $0$

Question 9

A tangent is drawn to the parabola $y^{2} = 6x$ which is perpendicular to the line $2x + y = 1$. Which of the following points does NOT lie on it ?

Accepted Answer

(D) $(5, 4)$

Answer

(A) $(0, 3)$

Answer

(B) $(-6, 0)$

Answer

(C) $(4, 5)$

Question 10

Let f, g: $N \rightarrow N$ such that $f(n + 1) = f(n) + f(1)$ $\forall n \in N$ and g be any arbitrary function. Which of the following statements is NOT true ?

Accepted Answer

(C) If g is onto, then fog is one-one

Answer

(A) f is one-one

Answer

(B) If fog is one-one, then g is one-one

Answer

(D) If f is onto, then $f(n) = n\ \forall n \in N$

Question 11

Let the lines $(2 - i)z = (2 + i)\bar{z}$ and $(2 + i)z + (i - 2)\bar{z} - 4i = 0$, (here $i^{2} = -1$) be normal to a circle C. If the line $iz + \bar{z} + 1 + i = 0$ is tangent to this circle C, then its radius is :

Accepted Answer

(C) $\frac{3}{2\sqrt{2}}$

Answer

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

Answer

(B) $3\sqrt{2}$

Answer

(D) $\frac{1}{2\sqrt{2}}$

Question 12

All possible values of $	heta \in [0, 2\pi]$ for which $\sin 2	heta + 	an 2	heta > 0$ lie in:

Accepted Answer

(B) $\left(0, \frac{\pi}{4}\right) \cup \left(\frac{\pi}{2}, \frac{3\pi}{4}\right) \cup \left(\pi, \frac{5\pi}{4}\right) \cup \left(\frac{3\pi}{2}, \frac{7\pi}{4}\right)$

Answer

(A) $\left(0, \frac{\pi}{2}\right) \cup \left(\pi, \frac{3\pi}{2}\right)$

Answer

(C) $\left(0, \frac{\pi}{2}\right) \cup \left(\frac{\pi}{2}, \frac{3\pi}{4}\right) \cup \left(\pi, \frac{7\pi}{6}\right)$

Answer

(D) $\left(0, \frac{\pi}{4}\right) \cup \left(\frac{\pi}{2}, \frac{3\pi}{4}\right) \cup \left(\frac{3\pi}{2}, \frac{11\pi}{6}\right)$

Question 13

The image of the point (3,5) in the line $x - y + 1 = 0$, lies on :

Accepted Answer

(A) $(x - 2)^{2} + (y - 4)^{2} = 4$

Answer

(B) $(x - 4)^{2} + (y + 2)^{2} = 16$

Answer

(C) $(x - 4)^{2} + (y - 4)^{2} = 8$

Answer

(D) $(x - 2)^{2} + (y - 2)^{2} = 12$

Question 14

If Rolle's theorem holds for the function $f(x) = x^{3} - ax^{2} + bx - 4$, $x \in [1, 2]$ with $f'\left(\frac{4}{3}\right) = 0$, then ordered pair (a, b) is equal to :

Accepted Answer

(B) $(5, 8)$

Answer

(A) $(-5, 8)$

Answer

(C) $(5, -8)$

Answer

(D) $(-5, -8)$

Question 15

If the curves, $\frac{x^{2}}{a} + \frac{y^{2}}{b} = 1$ and $\frac{x^{2}}{c} + \frac{y^{2}}{d} = 1$ intersect each other at an angle of $90^{\circ}$, then which of the following relations is true ?

Accepted Answer

(B) $a - b = c - d$

Answer

(A) $a + b = c + d$

Answer

(C) $ab = \frac{c+d}{a+b}$

Answer

(D) $a - c = b + d$

Question 16

$\lim\limits_{n 	o \infty} \left( 1 + \dfrac{1 + \frac{1}{2} + \dots + \frac{1}{n}}{n^2} ight)^{n}$ is equal to :

Accepted Answer

(C) $1$

Answer

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

Answer

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

Answer

(D) $0$

Question 17

The total number of positive integral solutions (x, y, z) such that $xyz = 24$ is

Accepted Answer

(D) $30$

Answer

(A) $36$

Answer

(B) $45$

Answer

(C) $24$

Question 18

If a curve passes through the origin and the slope of the tangent to it at any point $(x, y)$ is $\dfrac{x^2 - 4x + y + 8}{x - 2}$, then this curve also passes through the point :

Accepted Answer

(D) $(5, 5)$

Answer

(A) $(4, 5)$

Answer

(B) $(5, 4)$

Answer

(C) $(4, 4)$

Question 19

The value of $\int\limits_{-1}^{1} x^2 e^{[x^3]} dx$, where $[t]$ denotes the greatest integer $\le t$, is :

Accepted Answer

(C) $\frac{e+1}{3e}$

Answer

(A) $\frac{e+1}{3}$

Answer

(B) $\frac{e-1}{3e}$

Answer

(D) $\frac{1}{3e}$

Question 20

When a missile is fired from a ship, the probability that it is intercepted is $\frac{1}{3}$ and the probability that the missile hits the target, given that it is not intercepted, is $\frac{3}{4}$. If three missiles are fired independently from the ship, then the probability that all three hit the target, is:

Accepted Answer

(A) $\frac{1}{8}$

Answer

(B) $\frac{1}{27}$

Answer

(C) $\frac{3}{4}$

Answer

(D) $\frac{3}{8}$

Question 21

Let $A_1, A_2, A_3, \dots$ be squares such that for each $n \ge 1$, the length of the side of $A_n$ equals the length of diagonal of $A_{n+1}$. If the length of $A_1$ is 12 cm, then the smallest value of $n$ for which area of $A_n$ is less than one, is __________.

Accepted Answer

9

Question 22

The graphs of sine and cosine functions, intersect each other at a number of points and between two consecutive points of intersection, the two graphs enclose the same area A. Then $A^4$ is equal to __________

Accepted Answer

64

Question 23

The locus of the point of intersection of the lines $(\sqrt{3})kx + ky - 4\sqrt{3} = 0$ and $\sqrt{3}x - y - 4(\sqrt{3})k = 0$ is a conic, whose eccentricity is __________.

Accepted Answer

2

Question 24

If $A = \begin{bmatrix} 0 & -	an\left(\frac{	heta}{2}ight) \ 	an\left(\frac{	heta}{2}ight) & 0 \end{bmatrix}$ and $(I_2 + A)(I_2 - A)^{-1} = \begin{bmatrix} a & -b \ b & a \end{bmatrix}$, then $13(a^2 + b^2)$ is equal to _______.

Accepted Answer

13

Question 25

Let $f(x)$ be a polynomial of degree 6 in $x$, in which the coefficient of $x^6$ is unity and it has extrema at $x = -1$ and $x = 1$. If $\lim\limits_{x 	o 0} \dfrac{f(x)}{x^3} = 1$, then $5 \cdot f(2)$ is equal to __________

Accepted Answer

144

Question 26

The number of points, at which the function $f(x) = |2x + 1| - 3|x + 2| + |x^2 + x - 2|$, $x \in R$ is not differentiable, is __________.

Accepted Answer

2

Question 27

If the system of equations
$kx + y + 2z = 1$
$3x - y - 2z = 2$
$-2x - 2y - 4z = 3$
has infinitely many solutions, then $k$ is equal to ___________.

Accepted Answer

21

Question 28

Let $\vec{a} = \hat{i} + 2\hat{j} - \hat{k}$, $\vec{b} = \hat{i} - \hat{j}$ and $\vec{c} = \hat{i} - \hat{j} - \hat{k}$ be three given vectors. If $\vec{r}$ is a vector such that $\vec{r} 	imes \vec{a} = \vec{c} 	imes \vec{a}$ and $\vec{r} \cdot \vec{b} = 0$, then $\vec{r} \cdot \vec{a}$ is equal to ________

Accepted Answer

12

Question 29

Let $A = \begin{bmatrix} x & y & z \ y & z & x \ z & x & y \end{bmatrix}$, where $x$, $y$ and $z$ are real numbers such that $x + y + z > 0$ and $xyz = 2$. If $A^2 = I_3$, then the value of $x^3 + y^3 + z^3$ is ________.

Accepted Answer

7

Question 30

The total number of numbers, lying between 100 and 1000 that can be formed with the digits 1, 2, 3, 4, 5, if the repetition of digits is not allowed and numbers are divisible by either 3 or 5 is _________.

Accepted Answer

32

Question 31

A 5V battery is connected across the points X and Y. Assume $D_1$ and $D_2$ to be normal silicon diodes. Find the current supplied by the battery if the +ve terminal of the battery is connected to point X.

Accepted Answer

(C) ~ 0.43 A

Answer

(A) ~0.86 A

Answer

(B) ~0.5 A

Answer

(D) ~ 1.5 A

Question 32

A solid sphere of radius R gravitationally attracts a particle placed at 3R from its centre with a force $F_1$. Now a spherical cavity of radius $\left(\dfrac{R}{2}\right)$ is made in the sphere (as shown in figure) and the force becomes $F_2$. The value of $F_1 : F_2$ is :

Accepted Answer

(A) 41 : 50

Answer

(B) 36 : 25

Answer

(C) 50 : 41

Answer

(D) 25 : 36

Question 33

A student is performing the experiment of resonance column. The diameter of the column tube is 6 cm. The frequency of the tuning fork is 504 Hz. Speed of the sound at the given temperature is 336 m/s. The zero of the metre scale coincides with the top end of the resonance column tube. The reading of the water level in the column when the first resonance occurs is :

Accepted Answer

(B) 14.8 cm

Answer

(A) 13 cm

Answer

(C) 16.6 cm

Answer

(D) 18.4 cm

Question 34

A diatomic gas, having $C_p = \dfrac{7}{2}R$ and $C_v = \dfrac{5}{2}R$, is heated at constant pressure. The ratio dU : dQ : dW

Accepted Answer

(B) 5 : 7 : 2

Answer

(A) 3 : 7 : 2

Answer

(C) 5 : 7 : 3

Answer

(D) 3 : 5 : 2

Question 35

Given below are two statements :
Statement I : A speech signal of 2 kHz is used to modulate a carrier signal of 1 MHz. The bandwidth requirement for the signal is 4 kHz.
Statement II : The side band frequencies are 1002 kHz and 998 kHz.
In the light of the above statements, choose the correct answer from the options given below :

Accepted Answer

(D) Both statement I and statement II are true

Answer

(A) Both statement I and statement II are false

Answer

(B) Statement I is false but statement II is true

Answer

(C) Statement I is true but statement II is false

Question 36

The current (i) at time t=0 and $t = \infty$ respectively for the given circuit is :

Accepted Answer

(C) $\dfrac{5E}{18}, \dfrac{10E}{33}$

Answer

(A) $\dfrac{18E}{55}, \dfrac{5E}{18}$

Answer

(B) $\dfrac{5E}{18}, \dfrac{18E}{55}$

Answer

(D) $\dfrac{10E}{33}, \dfrac{5E}{18}$

Question 37

Two satellites A and B of masses 200 kg and 400 kg are revolving round the earth at height of 600 km and 1600 km respectively.
If $T_A$ and $T_B$ are the time periods of A and B respectively then the value of $T_B - T_A$ :
[Given : radius of earth = 6400 km, mass of earth = $6 	imes 10^{24}$ kg]

Accepted Answer

(C) $1.33 	imes 10^3$ s

Answer

(A) $4.24 	imes 10^2$ s

Answer

(B) $3.33 	imes 10^2$ s

Answer

(D) $4.24 	imes 10^3$ s

Question 38

An engine of a train, moving with uniform acceleration, passes the signal post with velocity u and the last compartment with velocity v. The velocity with which middle point of the train passes the signal post is :

Accepted Answer

(C) $\sqrt{\dfrac{v^2 + u^2}{2}}$

Answer

(A) $\sqrt{\dfrac{v^2 - u^2}{2}}$

Answer

(B) $\dfrac{v - u}{2}$

Answer

(D) $\dfrac{u + v}{2}$

Question 39

A proton, a deuteron and an α particle are moving with same momentum in a uniform magnetic field. The ratio of magnetic forces action on them is ________ and their speed is ______, in the ratio.

Accepted Answer

(A) 2 : 1 : 1 and 4 : 2 : 1

Answer

(B) 1 : 2 : 4 and 2 : 1 :1

Answer

(C) 1 : 2 : 4 and 1 : 1 : 2

Answer

(D) 4 : 2 : 1 and 2 : 1 : 1

Question 40

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : When a rod lying freely is heated, no thermal stress is developed in it.
Reason R : On heating, the length of the rod increases.
In the light of the above statements, choose the corect answer from the options given below :

Accepted Answer

(C) Both A and R are true but R is NOT the correct explanation of A

Answer

(A) A is true but R is false

Answer

(B) Both A and R are true and R is the correct explanation of A

Answer

(D) A is false but R is true

Question 41

In an octagon ABCDEFGH of equal side, what is the sum of
$\overrightarrow{AB} + \overrightarrow{AC} + \overrightarrow{AD} + \overrightarrow{AE} + \overrightarrow{AF} + \overrightarrow{AG} + \overrightarrow{AH}$
If, $\overrightarrow{AO} = 2\hat{i} + 3\hat{j} - 4\hat{k}$

Accepted Answer

(A) $16\hat{i} + 24\hat{j} - 32\hat{k}$

Answer

(B) $-16\hat{i} - 24\hat{j} - 32\hat{k}$

Answer

(C) $-16\hat{i} - 24\hat{j} + 32\hat{k}$

Answer

(D) $-16\hat{i} + 24\hat{j} + 32\hat{k}$

Question 42

Two radioactive substances X and Y originally have $N_1$ and $N_2$nuclei respectively. Half life of X is half of the half life of Y. After there half lives of Y, number of nuclei of both are equal. The ratio $\dfrac{N_1}{N_2}$ will be equal to :

Accepted Answer

(A) $\dfrac{8}{1}$

Answer

(B) $\dfrac{1}{8}$

Answer

(C) $\dfrac{3}{1}$

Answer

(D) $\dfrac{1}{3}$

Question 43

Match List –I with List- II :
List-I
(a)h (Planck's constant)
(b)E (kinetic energy)
(c)V (electric potential)
(d)P (linear momentum)
List-II
(i) $[M\,L\,T^{-1}]$
(ii) $[M\,L^2\,T^{-1}]$
(iii) $[M\,L^2\,T^{-2}]$
(iv) $[ML^2I^{-1}\,T^{-3}]$
Choose the correct answer from the options given below :

Accepted Answer

(A) (a) → (ii), (b) → (iii), (c) → (iv), (d) → (i)

Answer

(B) (a) → (i), (b) → (ii), (c) → (iv), (d) → (iii)

Answer

(C) (a) → (iii), (b) → (ii), (c) → (iv), (d) → (i)

Answer

(D) (a) → (iii), (b) → (iv), (c) → (ii), (d) → (i)

Question 44

The pitch of the screw guage is 1 mm and there are 100 divisions on the circular scale. When nothing is put in between the jaws, the zero of the circular scale lines 8 divisions below the reference line. When a wire is placed between the jaws, the first linear scale division is clearly visible while $72^{nd}$ division on circular scale coincides with the reference line. The radius of the wire is :

Accepted Answer

(C) 0.82 mm

Answer

(A) 1.64 mm

Answer

(B) 1.80 mm

Answer

(D) 0.90 mm

Question 45

If the time period of a two meter long simple pendulum is 2 s, the acceleration due to gravity at the place where pendulum is executing S.H.M. is :

Accepted Answer

(A) $2\pi^2 \mathrm{ms}^{-2}$

Answer

(B) $16 \mathrm{m/s}^2$

Answer

(C) $9.8 \mathrm{ms}^{-2}$

Answer

(D) $\pi^2 \mathrm{ms}^{-2}$

Question 46

An $\alpha$ particle and a proton are accelerated from rest by a potential difference of 200 V. After this, their de Broglie wavelengths are $\lambda_\alpha$ and $\lambda_p$ respectively. The ratio $\dfrac{\lambda_p}{\lambda_\alpha}$ is :

Accepted Answer

(B) 2.8

Answer

(A) 8

Answer

(C) 3.8

Answer

(D) 7.8

Question 47

Given below are two statements : one is labelled as Assertion A and the other is labelled as reason R.
Assertion A : The escape velocities of planet A and B are same. But A and B are of unequal mass.
Reason R : The product of their mass and radius must be same. $M_1R_1 = M_2R_2$
In the light of the above statements, choose the most appropriate answer from the options given below:

Accepted Answer

(B) A is correct but R is not correct

Answer

(A) Both A and R are correct but R is NOT the correct explanation of A

Answer

(C) Both A and R are correct and R is the correct explanation of A

Answer

(D) A is not correct but R is correct

Question 48

The angular frequency of alterlating current in a L-C-R circuit is 100 rad/s. The components connected are shown in the figure. Find the value of inductance of the coil and capacity of condenser.

Accepted Answer

(A) 0.8 H and 250 $\mu$F

Answer

(B) 0.8 H and 150 $\mu$F

Answer

(C) 1.33 H and 250 $\mu$F

Answer

(D) 1.33 H and 150 $\mu$F

Question 49

Two coherent light sources having intensity in the ratio 2x produce an interference pattern. The ratio $\dfrac{I_{max} - I_{min}}{I_{max} + I_{min}}$ will be :

Accepted Answer

(C) $\dfrac{2\sqrt{2x}}{2x + 1}$

Answer

(A) $\dfrac{2\sqrt{2x}}{x + 1}$

Answer

(B) $\dfrac{\sqrt{2x}}{2x + 1}$

Answer

(D) $\dfrac{\sqrt{2x}}{x + 1}$

Question 50

Magnetic fields at two points on the axis of a circular coil at a distance of 0.05 m and 02 m from the centre are in the rato 8 : 1. The radius of coil is ________

Accepted Answer

(C) 0.1 m

Answer

(A) 0.15 m

Answer

(B) 0.2 m

Answer

(D) 1.0 m

Question 51

The same size images are formed by a convex lens when the object is placed at 20 cm or at 10 cm from the lens. The focal length of convex lens is ________ cm.

Accepted Answer

15

Question 52

The electric field in a region is given by $\vec{E} = \left(\dfrac{3}{5}E_0\hat{i} + \dfrac{4}{5}E_0\hat{j}\right)\dfrac{N}{C}$. The ratio of flux of reported field through the rectangular surface of area 0.2 $m^2$ (parallel to y-z plane) to that of the surface of area 0.3 $m^2$ (parallel to x-z plane) is a : b, where a = __________
[Here $\hat{i}$, $\hat{j}$ and $\hat{k}$ are unit vectors along x, y and z-axes respectively]

Accepted Answer

1

Question 53

512 identical drops of mercury are charged to a potential of 2 V each. The drops are joined to form a single drop. The potential of this drop is _____ V.

Accepted Answer

128

Question 54

The potential energy (U) of a diatomic molecule is a function dependent on r (interatomic distance) as $U = \dfrac{\alpha}{r^{10}} - \dfrac{\beta}{r^5} - 3$ Where, a and b are positive constants. The equilibrium distance between two atoms will $\left(\dfrac{2\alpha}{\beta}\right)^{\frac{a}{b}}$. Where a = ________

Accepted Answer

1

Question 55

A small bob tied at one end of a thin string of length 1m is describing a vertical circle so that the maximum and minimum tension in the string are in the rato 5 : 1. The velocity of the bob at the highest position is ________ m/s. (take g=10 $m/s^2$)

Accepted Answer

5

Question 56

In a certain themodynamical process, the pressure ofa gas depends on its volume as $kV^3$ . The work done when the temperature changes from 100ºC to 300ºC will be _____ nR, where n denotes number of moles of a gas.

Accepted Answer

50

Question 57

In the given circuit of potentiometer, the potentital difference E across AB (10 m length) is larger than $E_1$ and $E_2$ as well. For key $K_1$ (closed), the jockey is adjusted to touch the wire at point $J_1$ so that there is no deflection in the galvanometer. Now the first battery ($E_1$) is replaced by second battery ($E_2$) for working by making $K_1$ open and $E_2$ closed. The galvanometer gives then null deflection at $J_2$. The value of $\dfrac{E_1}{E_2}$ is $\dfrac{a}{b}$, where a = _____.

Accepted Answer

1

Question 58

A monoatomic gas of mass 4.0 u is kept in an insulated container. Container is moving with velocity 30 m/s. If container is suddenly stopped then change in temperature of the gas (R=gas constant) is $\dfrac{x}{3R}$. Value of x is ________ .

Accepted Answer

3600

Question 59

A coil of inductance 2 H having negligible resistance is connected to a source of supply whose voltage is given by V =3t volt. (where t is in second). If the voltage is applied when t = 0, then the energy stored in the coil after 4 s is ________ J.

Accepted Answer

144

Question 60

A transmitting station releases waves of wavelength 960 m. A capacitor of 256 $\mu$F is used in the resonant circuit. The self inductance of coil necessary for resonance is ______ $	imes 10^{-8}$H.

Accepted Answer

10

Question 61

Ellingham diagram is a graphical representation of:

Accepted Answer

(A) ΔG vs T

Answer

(B) (ΔG − TΔS) vs T

Answer

(C) ΔH vs T

Answer

(D) ΔG vs P

Question 62

Which of the following equation depicts the oxidizing nature of H$_{2}$O$_{2}$?

Accepted Answer

(C) 2I$^{-}$ + H$_{2}$O$_{2}$ + 2H$^{+}$ → I$_{2}$ + 2H$_{2}$O

Answer

(A) Cl$_{2}$ + H$_{2}$O$_{2}$ → 2HCl + O$_{2}$

Answer

(B) KIO$_{4}$ + H$_{2}$O$_{2}$ → KIO$_{3}$ + H$_{2}$O + O$_{2}$

Answer

(D) I$_{2}$ + H$_{2}$O$_{2}$ + 2OH$^{-}$ → 2I$^{-}$ + 2H2O + O$_{2}$

Question 63

In Freundlich adsorption isotherm at moderate pressure, the extent of adsorption $\left(\dfrac{x}{m}\right)$ is directly proportional to P$^{x}$. The value of x is:

Accepted Answer

(D) $\dfrac{1}{n}$

Answer

(A) ∞

Answer

(B) 1

Answer

(C) zero

Question 64

According to molecular orbital theory, the species among the following that does not exist is:

Accepted Answer

(D) Be$_{2}$

Answer

(A) He$_{2}^{-}$

Answer

(B) He$_{2}^{+}$

Answer

(C) O$_{2}^{2-}$

JEE Main 25 February 2021 Shift 1 Question Paper with Answers

Physics — JEE Main 25 February 2021 Shift 1

Chemistry — JEE Main 25 February 2021 Shift 1

Mathematics — JEE Main 25 February 2021 Shift 1

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