← JEE MAINS
JEE · combined subjects

JEE Main 2021 (25 Feb Shift 2)

2021 · 90 questions · First 10 Solutions Free
Questions 1–10 have full step-by-step solutions visible. Sign in to unlock all 90 →
Q1 mcq
Thermodynamic process is shown below on a $P - V$ diagram for one mole of an ideal gas. If $V_{2} = 2V_{1}$ , then the ratio of temperature $\frac{T_{2}}{T_{1}}$ is :
Question 1 image
a.
$\sqrt{2}$ Correct Answer
b.
$\frac{1}{\sqrt{2}}$
c.
$\frac{1}{2}$
d.
$2$

No explanation saved for this question yet.

Q2 nat
Two identical conducting spheres with negligible volume have $2. 1\, nC$ and $-0. 1\, nC$ charges, respectively. They are brought into contact and then separated by a distance of $0. 5\,m$ . The electrostatic force acting between the spheres is ___ $\times 10^{-9}\,N$ . [Given : $4\pi \epsilon _{0} = \frac{1}{9\times 10^{9}}$ SI unit]
✓ Accepted Answer: 36

No explanation saved for this question yet.

Q3 nat
A reversible heat engine converts one-fourth of the heat input into work. When the temperature of the sink is reduced by $52\,K,$ its efficiency is doubled. The temperature in Kelvin of the source will be ___ .
✓ Accepted Answer: 208

No explanation saved for this question yet.

Q4 mcq
An $L.C.R.$ circuit contains resistance of $110\,\Omega$ and a supply of $220\,V$ at $300\, rad \,s^{-1}$ angular frequency. If only capacitance is removed from the circuit, current lags behind the voltage by $45^{\circ}$ . If on the other hand, the only the inductor is removed the current leads by $45^{\circ}$ with the applied voltage. The $R.M.S.$ current flowing in the circuit will be:
a.
$2. 5\,A$
b.
$2\,A$ Correct Answer
c.
$1\,A$
d.
$1. 5\,A$

No explanation saved for this question yet.

Q5 mcq
A stone is dropped from the top of a building. When it crosses a point $5\,m$ below the top, another stone starts to fall from a point $25\,m$ below the top. Both stones reach the bottom of building simultaneously. The height of the building is :
a.
$25\,m$
b.
$45\,m$ Correct Answer
c.
$35\,m$
d.
$50\,m$

No explanation saved for this question yet.

Q6 mcq
Match List I with List II. List I List II (a) Rectifier (i) Used either for stepping up or stepping down the A.C. voltage (b)Stabilizer (ii) Used to convert A.C. voltage into D.C. voltage (c) Transformer(iii)Used to remove any ripple in the rectified output voltage Used for constant output voltage even when the input voltage (iv) (d)Filter or load current change Choose the correct answer from the options given below:
a.
$(a) -(ii), \,(b) -(iv), \,(c) -(i), \,(d) -(iii)$ Correct Answer
b.
$(a) -(ii), \,(b) -(i), \,(c) -(iv), \,(d) -(iii)$
c.
$(a) -(ii), \,(b) -(i), \,(c) -(iii), \,(d) -(iv)$
d.
$(a) -(iii), \,(b) -(iv), \,(c) -(i), \,(d) -(ii)$

No explanation saved for this question yet.

Q7 nat
The wavelength of an X-ray beam is $10\,$ ā„«. The mass of a fictitious particle having the same energy as that of the X-ray photons is $\frac{x}{3} h\, kg.$ The value of $x$ is ___ . ( $h=$ Planck's constant)
✓ Accepted Answer: 10

No explanation saved for this question yet.

Q8 mcq
Given below are two statements: Statement I: In a diatomic molecule, the rotational energy at a given temperature obeys Maxwell's distribution. Statement II : In a diatomic molecule, the rotational energy at a given temperature equals the translational kinetic energy for each molecule. In the light of the above statements, choose the correct answer from the options given below:
a.
Statement $I$ is false but Statement $II$ is true.
b.
Statement $I$ is true but Statement $II$ is false. Correct Answer
c.
Both Statement $I$ and Statement $II$ are true.
d.
Both Statement $I$ and Statement $II$ are false.

No explanation saved for this question yet.

Q9 mcq
The point $A$ moves with a uniform speed along the circumference of a circle of radius $0. 36\,m$ and covers $30^{\circ}$ in $0. 1\,s$ . The perpendicular projection $P$ from $A$ on the diameter $MN$ represents the simple harmonic motion of $P$ . The restoration force per unit mass when $P$ touches $M$ will be :
Question 9 image
a.
$0. 49\,N$
b.
$9. 87\,N$ Correct Answer
c.
$50\,N$
d.
$100\,N$

No explanation saved for this question yet.

Q10 mcq
$Y =Asin(\omega t+\phi _{0})$ is the time-displacement equation of a $SHM.$ At $t= 0$ the displacement of the particle is $Y = \frac{A}{2}$ and it is moving along negative $x$ -direction. Then the initial phase angle $\phi _{0}$ will be:
a.
$\frac{2\pi}{3}$
b.
$\frac{\pi}{6}$
c.
$\frac{5\pi}{6}$ Correct Answer
d.
$\frac{\pi}{3}$

No explanation saved for this question yet.

🎉 10 Free Sample Solutions Completed

Unlock All 90 Questions & Solutions

Sign up free in seconds to unlock step-by-step AI answers for the remaining 80 questions.

Q11 mcq
Two identical springs of spring constant $2k$ are attached to a block of mass $m$ and to fixed support (see figure). When the mass is displaced from equilibrium position on either side, it executes simple harmonic motion. The time period of oscillations of this system is :
Question 11 image
a.
$\pi \sqrt{\frac{m}{k}}$
b.
$2\pi \sqrt{\frac{m}{2k}}$
c.
$\pi \sqrt{\frac{m}{2k}}$
d.
$2\pi \sqrt{\frac{m}{k}}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q12 mcq
If $e$ is the electronic charge, $c$ is the speed of light in free space and $h$ is Planck's constant, the quantity $_{4\pi \epsilon _{0}}_{hc}$ has dimensions of :
a.
$[MLT^{0}]$
b.
$[M^{0}\,L^{0}\,T^{0}]$
c.
$[MLT^{-1}]$
d.
$[LC^{-1}]$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q13 nat
Two small spheres each of mass $10\, mg$ are suspended from a point by threads $0. 5\,m$ long. They are equally charged and repel each other to a distance of $0. 20\,m$ . The charge on each of the sphere is $\frac{a}{21} \times 10^{-8}\,C.$ The value of $a$ will be ___.[Given $g= 10\,m\,s^{-2}$ ]
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q14 mcq
The wavelength of the photon emitted by a hydrogen atom when an electron makes a transition from $n= 2$ to $n= 1$ state is:
a.
$121. 8\, nm$
b.
$194. 8\, nm$
c.
$490. 7\, nm$
d.
$913. 3\, nm$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q15 nat
The peak electric field produced by the radiation coming from the $8\,W$ bulb at a distance of $10\,m$ is $\frac{x}{10}\sqrt{\,} \frac{\mu _{0}c}{\pi} \,V\,m^{-1}$ . The efficiency of the bulb is $10%$ and it is a point source. The value of $x$ is,
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q16 mcq
If a message signal of frequency $f_{m}$ is amplitude modulated with a carrier signal of frequency $f_{c}$ and radiated through an antenna, the wavelength of the corresponding signal in air is
a.
$\frac{c}{f_{c}-f_{m}}$
b.
$\frac{c}{f_{m}}$
c.
$\frac{c}{f_{c}}$
d.
$\frac{c}{f_{c}+f_{m}}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q17 mcq
For extrinsic semiconductors; when doping level is increased;
a.
Fermi-level of $p$ and $n$ - type semiconductors will not be affected.
b.
Fermi-level of $p$ -type semiconductor will go upward and Fermi-level of $n$ -type semiconductors will go downward.
c.
Fermi-level of both p-type and n-type semiconductors will go upward for $T >T_{F}\,K$ and downward for $T <T_{F}\,K,$ where $T_{F}$ is Fermi temperature.
d.
Fermi-level of $p$ - type semiconductors will go downward and Fermi-level of $n$ - type semiconductor will go upward.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q18 mcq
The truth table for the following logic circuit is :
Question 18 image
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q19 mcq
An electron with kinetic energy $K_{1}$ enters between parallel plates of a capacitor at an angle $\alpha$ with the plates. It leaves the plates at angle $\beta$ with kinetic energy $K_{2}.$ Then the ratio of kinetic energies $K_{1} :K_{2}$ will be :
a.
$\frac{sin^{2}\beta}{cos^{2}\alpha}$
b.
$\frac{cos\beta}{sin\alpha}$
c.
$\frac{cos\beta}{cos\alpha}$
d.
$\frac{cos^{2}\beta}{cos^{2}\alpha}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q20 mcq
Consider the diffraction pattern obtained from the sunlight incident on a pinhole of diameter $0. 1\,\mu m.$ If the diameter of the pinhole is slightly increased, it will affect the diffraction pattern such that
a.
its size increases, and intensity increases
b.
its size decreases, and intensity decreases
c.
its size decreases, but intensity increases
d.
its size increases, but intensity decreases
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q21 nat
A current of $6\,A$ enters one corner $P$ of an equilateral triangle $PQR$ having $3$ wires of resistance $2\,\Omega$ each and leaves by the corner $R.$ The currents $i_{1}$ in ampere is
Question 21 image
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q22 mcq
The stopping potential for electrons emitted from a photosensitive surface illuminated by light of wavelength $491\, nm$ is $0. 710\,V.$ When the incident wavelength is changed to a new value, the stopping potential is $1. 43\,V.$ The new wavelength is :
a.
$382\, nm$
b.
$309\, nm$
c.
$329\, nm$
d.
$400\, nm$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q23 nat
The initial velocity $v_{i}$ required to project a body vertically upward from the surface of the earth to reach a height of $10R$ , where $R$ is the radius of the earth, may be described in terms of escape velocity $v_{e}$ such that $v_{i} =\sqrt{\frac{x}{y}} \times v_{e}$ . The value of $x$ will be
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q24 nat
The percentage increase in the speed of transverse waves produced in a stretched string if the tension is increased by $4%$ , will be ___ $%$ .
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q25 mcq
In a ferromagnetic material, below the curie temperature, a domain is defined as:
a.
a macroscopic region with saturation magnetization.
b.
a macroscopic region with consecutive magnetic dipoles oriented in opposite direction.
c.
a macroscopic region with zero magnetization.
d.
a macroscopic region with randomly oriented magnetic dipoles.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q26 nat
Two particles having masses $4\,g$ and $16\,g$ respectively are moving with equal kinetic energies. The ratio of the magnitudes of their linear momentum is $n: 2$ . The value of $n$ will be ___.
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q27 mcq
A sphere of radius $a$ and mass $m$ rolls along a horizontal plane with constant speed $v_{0}$ . It encounters an inclined plane at angle $\theta$ and climbs upward. Assuming that it rolls without slipping, how far up the sphere will travel?
Question 27 image
a.
$\frac{2}{5} \frac{v^{2}_{0}}{gsin\theta}$
b.
$\frac{7v^{2}_{0}}{10\,gsin\theta}$
c.
$\frac{v^{2}_{0}}{5gsin\theta}$
d.
$\frac{v^{2}_{0}}{2gsin\theta}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q28 mcq
A charge is placed at one corner of a cube as shown in figure. The flux of electrostatic field $q \vec{E}$ through the shaded area is:
Question 28 image
a.
$\frac{q}{8\epsilon _{0}}$
b.
$\frac{q}{24\epsilon _{0}}$
c.
$\frac{q}{48\epsilon _{0}}$
d.
$\frac{q}{4\epsilon _{0}}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q29 mcq
An electron of mass $m_{e}$ and a proton of mass $m_{p} = 1836\,m_{e}$ are moving with the same speed. The ratio of their de Broglie wavelength $\frac{\lambda _{electron}}{\lambda _{proton}}$ will be :
a.
$1836$
b.
$\frac{1}{1836}$
c.
$918$
d.
$1$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q30 nat
If $\vec{P} \times \vec{Q}= \vec{Q}\times \vec{P}$ , the angle between $\vec{P}$ and $\vec{Q}$ is $\theta (0^{\circ}<\theta < 360^{\circ})$ . The value of $\theta$ will be ___ $^{\circ}$ .
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q31 nat
The spin only magnetic moment of a divalent ion in aqueous solution (atomic number $29$ ) is ___ $BM$ .
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q32 nat
The unit cell of copper corresponds to a face centered cube of edge length $3. 596\,$ ƅwith one copper atom at each lattice point. The calculated density of copper in $kg /m^{3}$ is ___ . [Molar mass of $Cu : 63. 54\,g;$ Avogadro Number $= 6. 022 \times 10^{23}\,J$ ]
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q33 mcq
Given below are two statements: Statement I: The $pH$ of rain water is normally $~5. 6$ . Statement II : If the $pH$ of rain water drops below $5. 6$ , it is called acid rain. In the light of the above statements, choose the correct answer from the options given below:
a.
Both Statement $I$ and Statement $II$ are true.
b.
Statement $I$ is false but Statement $II$ is true.
c.
Statement $I$ is true but Statement $II$ is false.
d.
Both Statement $I$ and Statement $II$ are false.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q34 mcq
Given below are two statements: Statement I : $\alpha$ and $\beta$ forms of sulphur can change reversibly between themselves with slow heating or slow cooling. Statement II : At room temperature the stable crystalline form of sulphur is monoclinic sulphur. In the light of the above statements, choose the correct answer from the options given below:
a.
Both Statement $I$ and Statement $II$ are true.
b.
Statement $I$ is true but Statement $II$ is false.
c.
Statement $I$ is false but Statement $II$ is true.
d.
Both Statement $I$ and Statement $II$ are false.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q35 nat
Five moles of an ideal gas at $293\,K$ is expanded isothermally from an initial pressure of $2. 1\, MPa$ to $1. 3\, MPa$ against at constant external pressure $4. 3\, MPa$ . The heat transferred in this process is ___ $kJmol^{-1}$ . (Rounded-off to the nearest integer) [ Use $R= 8. 314\,J\, mol^{-1} \,K^{-1}$ ]
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q36 mcq
Given below are two statements: Statement I : The identification of $Ni^{2+}$ is carried out by dimethyl glyoxime in the presence of $NH_{4}OH$ . Statement II :The dimethyl glyoxime is a bidentate neutral ligand. In the light of the above statements, choose the correct answer from the options given below:
a.
Statement $I$ is false but Statement $II$ is true.
b.
Statement $I$ is true but Statement $II$ is false.
c.
Both Statement $I$ and Statement $II$ are true.
d.
Both Statement $I$ and Statement $II$ are false.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q37 mcq
The method used for the purification of Indium is:
a.
vapour phase refining
b.
liquation
c.
zone refining
d.
van Arkel method
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q38 mcq
Which one of the following statements is FALSE for hydrophilic sols?
a.
These sols are reversible in nature.
b.
Their viscosity is of the order of that of $H_{2}O$ .
c.
The sols cannot be easily coagulated.
d.
They do not require electrolytes for stability.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q39 mcq
The major components of German Silver are :
a.
$Zn, Ni$ and $Ag$
b.
$Cu, Zn$ and $Ni$
c.
$Ge, Cu$ and $Ag$
d.
$Cu, Zn$ and $Ag$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q40 mcq
The major product of the following reaction is :
Question 40 image
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q41 nat
Electromagnetic radiation of wavelength $663\, nm$ is just sufficient to ionise the atom of metal $A$ . The ionization energy of metal $A$ in $kJ \, mol^{-1}$ is ___. (Rounded-off to the nearest integer) $[h = 6. 63 \times 10^{-34} Js, c = 3. 00 \times 10^{8}\, ms^{-1}, \,N_{A} = 6. 02 \times 10^{23}\, mol^{-1}]$
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q42 mcq
Which of the following is correct structure of $\alpha$ -anomer of maltose?
Question 42 image
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q43 mcq
Which of the following compound is added to the sodium extract before addition of silver nitrate for testing of halogens?
a.
Nitric acid
b.
Sodium hydroxide
c.
Ammonia
d.
Hydrochloric acid
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q44 nat
Consider titration of $NaOH$ solution versus $1. 25\,M$ oxalic acid solution. At the end point following burette readings were obtained. (i) $4. 5\, mL$ (ii) $4. 5\, mL$ (iii) $4. 4\, mL$ (iv) $4. 4\, mL$ (v) $4. 4\, mL$ If the volume of oxalic acid taken was $10. 0\, mL$ then the molarity of the $NaOH$ solution is ___ $M$ . (Rounded- off to the nearest integer)
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q45 mcq
Water does not produce $CO$ on reacting with :
a.
$CO_{2}$
b.
$CH_{4}$
c.
$C_{3}H_{8}$
d.
$C$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q46 nat
Among the following, number of metal/s which can be used as electrodes in the photoelectric cell is ___ . (Integer answer) (A) $Li$ (B) $Na$ (C) $Rb$ (D) $Cs$
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q47 mcq
In which of the following order the given complex ions are arranged correctly with respect to their decreasing spin only magnetic moment? (i) $[FeF_{6}]^{3-}$ (ii) $[Co (NH_{3})_{6}]^{3+}$ (iii) $[NiCl_{4}]^{2-}$ (iv) $[Cu (NH_{3})_{4}]^{2+}$
a.
$(ii) > (i) > (iii) > (iv)$
b.
$(iii) > (iv) > (ii) > (i)$
c.
$(i) > (iii) > (iv) > (ii)$
d.
$(ii) > (iii) > (i) > (iv)$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q48 mcq
The solubility of $Ca (OH)_{2}$ in water is : [Given : The solubility product of $Ca (OH)_{2}$ in water $= 5. 5 \times 10^{-6}$ ]
a.
$1. 77 \times 10^{-2}$
b.
$1. 77 \times 10^{-6}$
c.
$1. 11 \times 10^{-2}$
d.
$1. 11 \times 10^{-6}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q49 mcq
The correct order of acid character of the following compounds is :
Question 49 image
a.
$IV > III > II > I$
b.
$II > III > IV > I$
c.
$III > II > I > IV$
d.
$I > II > III > IV$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q50 nat
Copper reduces $NO^{-}_{3}$ into $NO$ and $NO_{2}$ depending upon the concentration of $HNO_{3}$ in solution. (Assuming fixed $[Cu^{2+}]$ and $P_{NO} = P_{NO_{2}}$ ), the $HNO_{3}$ concentration at which the thermodynamic tendency for reduction of $NO^{-}_{3}$ into $NO$ and $NO_{2}$ by copper is same is $10^{x}\,M$ . The value of $2x$ is ___. (Rounded-off to the nearest integer) [Given, $E^{o}_{Cu^{2+}/ Cu} = 0. 34\,V, E^{o}_{NO^{-}_{3}}_{/ NO} = 0. 96\,V, E^{o}_{NO^{-}_{3}}_{/ NO_{2}} = 0. 79\,V$ and at $298\,K$ , $\frac{RT}{F}(2. 303) = 0. 059$ ]
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q51 mcq
The correct order of bond dissociation enthalpy of halogens is:
a.
$F_{2} > Cl_{2} > Br_{2} > I_{2}$
b.
$Cl_{2} > F_{2} > Br_{2} > I_{2}$
c.
$I_{2} > Br_{2} > Cl_{2} > F_{2}$
d.
$Cl_{2} > Br_{2} > F_{2} > I_{2}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q52 mcq
Correct statement about the given chemical reaction is
a.
Reaction is possible and compound (A) will be major product.
b.
$-NHĀØ_{2}$ group is ortho and para directive, so product (B) is not possible.
c.
Reaction is possible and compound (B) will be the major product.
d.
The reaction will form sulphonated product instead of nitration.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q53 mcq
Which among the following species has unequal bond lengths?
a.
$SiF_{4}$
b.
$SF_{4}$
c.
$XeF_{4}$
d.
$BF_{4}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q54 mcq
The major product of the following reaction is : $-CH_{3}CH_{2}CH = CH_{2}_{Rh \, catal}^{H_{2}/ CO}_{\vec{y}st}$
Question 54 image
a.
$CH_{3}CH_{2}CH = CH -CHO$
b.
$CH_{3}CH_{2}CH_{2}CH_{2}CHO$
c.
$CH_{3}CH_{2}CH_{2}CHO$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q55 nat
The rate constant of a reaction increases by five times on increase in temperature from $27^{\circ}C$ to $52^{\circ}C$ . The value of activation energy in $kJmol^{-1}$ is ___ .(Rounded-off to the nearest integer) $[R= 8. 314\,J\,K^{-1}\, mol^{-1}]$
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q56 mcq
Carbylamine test is used to detect the presence of primary amino group in an organic compound. Which of the following compound is formed when this test is performed with aniline?
Question 56 image
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q57 mcq
What is $'X'$ in the given reaction?
Question 57 image
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q58 mcq
The correct sequence of reagents used in the preparation of $4$ -bromo- $2$ -nitroethylbenzene from benzene is :
a.
$CH_{3}COCl / AlCl_{3}, Br_{2}/ AlBr_{3}, HNO_{3}/H_{2}SO_{4}, Zn / HCl$
b.
$CH_{3}COCl / AlCl_{3}, Zn -Hg / HCl, Br_{2}/ AlBr_{3}, HNO_{3}/H_{2}SO_{4}$
c.
$HNO_{3}/H_{2}SO_{4}, Br_{2}/ AlCl_{3}, CH_{3}COCl / AlCl_{3}, Zn -Hg / HCl$
d.
$Br_{2}/ AlBr_{3}, CH_{3}COCl / AlCl_{3}, HNO_{3}/H_{2}SO_{4}, Zn / HCl$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q59 nat
If a compound $AB$ dissociates to the extent of $75%$ in an aqueous solution, the molality of the solution which shows a $2. 5\,K$ rise in the boiling point of the solution is ___ molal. (Rounded-off to the nearest integer) $[K_{b} = 0. 52K\, kg \, mol^{-1}]$ .
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q60 nat
The number of compound/s given below which contain/s $-COOH$ group is ___ . (Integer answer) (A) Sulphanilic acid (B) Picric acid (C) Aspirin (D) Ascorbic acid
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q61 mcq
$1 -\alpha$ If for the matrix, $A=[ ], \,AA^{T} =I_{2}$ , then the value of $\alpha ^{4} +\beta ^{4}$ is : $\alpha \beta$
a.
$3$
b.
$1$
c.
$2$
d.
$4$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q62 mcq
If the curve $x^{2} + 2y^{2} = 2$ intersects the line $x+y= 1$ at two points $P$ and $Q$ , then the angle subtended by the line segment $PQ$ at the origin is
a.
$\frac{\pi}{2} -tan^{-1}(\frac{1}{3})$
b.
$\frac{\pi}{2} + tan^{-1}(\frac{1}{3} )$
c.
$\frac{\pi}{2} + tan^{-1}(\frac{1}{4})$
d.
$\frac{\pi}{2} -tan^{-1}(\frac{1}{4} )$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q63 mcq
$_{n}lim_{\rightarrow \infty \rightarrow } [\frac{1}{n} + \frac{n}{(n+1)^{2}} + \frac{n}{(n+2)^{2}} + … + \frac{n}{(2n-1)^{2}}]$ is equal to
a.
$\frac{1}{2}$
b.
$\frac{1}{4}$
c.
$\frac{1}{3}$
d.
$1$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q64 mcq
The shortest distance between the line $x- y= 1$ and the curve $x^{2} = 2y$ is:
a.
$\frac{1}{2}$
b.
$\frac{1}{\sqrt{2}}$
c.
$\frac{1}{2\sqrt{2}}$
d.
$0$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q65 mcq
In a group of $400$ people, $160$ are smokers and non-vegetarian; $100$ are smokers and vegetarian and the remaining $140$ are non-smokers and vegetarian. Their chances of getting a particular chest disorder are $35%, 20%$ and $10%$ respectively. A person is chosen from the group at random and is found to be suffering from the chest disorder. The probability that the selected person is a smoker and non-vegetarian is :
a.
$\frac{14}{45}$
b.
$\frac{7}{45}$
c.
$\frac{8}{45}$
d.
$\frac{28}{45}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q66 mcq
The minimum value of $f(x) =a^{a^{x}} +a^{1-a^{x}}$ , where $a, \,x\in R$ and $a> 0$ , is equal to:
a.
$a+ 1$
b.
$2a$
c.
$a+ \frac{1}{a}$
d.
$2\sqrt{a}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q67 mcq
The contrapositive of the statement "If you will work, you will earn money" is:
a.
If you will not earn money, you will not work
b.
To earn money, you need to work
c.
You will earn money, if you will not work
d.
If you will earn money, you will work
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q68 mcq
A plane passes through the points $A(1, 2, 3),B(2, 3, 1)$ and $C(2, 4, 2)$ . If $O$ is the origin and $P$ is $(2, -1, 1)$ $-$ , then the projection of $O\vec{P}$ on this plane is of length:
a.
$\sqrt{\frac{2}{5}}$
b.
$\sqrt{\frac{2}{7}}$
c.
$\sqrt{\frac{2}{3}}$
d.
$\sqrt{\frac{2}{11}}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q69 nat
The total number of two digit numbers $'n'$ , such that $3^{n} + 7^{n}$ is a multiple of $10$ , is ___ .
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q70 nat
If $_{x}lim_{\rightarrow 0\rightarrow } \frac{ax-(e^{4}^{x}-1)}{ax(e^{4}^{x}-1)}$ exists and is equal to $b$ , then the value of $a-2b$ is ___ .
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q71 mcq
If $\alpha ,\beta \in R$ are such that $1 -2i$ (here $i^{2} = -1$ ) is a root of $z^{2} +\alpha z+\beta = 0$ , then $(\alpha - \beta )$ is equal to:
a.
$-7$
b.
$7$
c.
$-3$
d.
$3$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q72 mcq
Let $A$ be a set of all $4$ -digit natural numbers whose exactly one digit is $7$ . Then the probability that a randomly chosen element of $A$ leaves remainder $2$ when divided by $5$ is:
a.
$\frac{1}{5}$
b.
$\frac{122}{297}$
c.
$\frac{97}{297}$
d.
$\frac{2}{9}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q73 mcq
Let $A$ be a $3 \times 3$ matrix with $det (A) = 4$ . Let $R_{i}$ denote the $i^{th}$ row of $A$ . If a matrix $B$ is obtained by performing the operation $R_{2} \rightarrow 2\rightarrow R_{2}+ 5R_{3}$ on $2\,A$ , then $det (B)$ is equal to :
a.
$64$
b.
$16$
c.
$128$
d.
$80$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q74 mcq
If $I_{n} =\int _{4}\frac{\pi}{\pi 2} cot^{n}xdx$ , then
a.
$I_{2}+I_{4}, (I_{3}+I_{5})^{2},I_{4}+I_{6}$ are in $G. P.$
b.
$I_{2}+I_{4},I_{3}+I_{5},I_{4}+I_{6}$ are in $A. P.$
c.
$\frac{1}{I_{2}+I_{4}}, \frac{1}{I_{3}+I_{5}}, \frac{1}{I_{4}+I_{6}}$ are in $A. P.$
d.
$\frac{1}{I_{2}+I_{4}}, \frac{1}{I_{3}+I_{5}}, \frac{1}{I_{4}+I_{6}}$ are in $G. P.$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q75 nat
$|$ $||$ A line $l$ passing through origin is perpendicular to the lines $l_{1} : \vec{r}= (3 +t)ˆi + (-1 + 2t)ˆj + (4 + 2t)ˆk$ $l_{2} : \vec{r}= (3 + 2s)ˆi + (3 + 2s)ˆj + (2 +s)ˆk$ If the co-ordinates of the point in the first octant on $l_{2}$ at a distance of $\sqrt{17}$ from the point of intersection of $l$ and $l_{1}$ are $(a, \,b, \,c)$ , then $18(a+b+c)$ is equal to ___ .
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q76 nat
A function $f$ is defined on $[-3, 3]$ as $min{ x , 2 - x^{2}}, -2 \leq x\leq 2$ $f(x) ={$ $[|x|]\,\,, \,\,2 < |x| \leq 3$ where $[x]$ denotes the greatest integer $\leq x$ . The number of points, where $f$ is not differentiable in $(-3, 3)$ is ___ .
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q77 mcq
The following system of linear equations $2x+ 3y+ 2z= 9$ $3x+ 2y+ 2z= 9$ $x- y+ 4z= 8$
a.
has infinitely many solutions
b.
has a unique solution
c.
has a solution $(\alpha ,\beta ,\gamma )$ satisfying $\alpha +\beta ^{2} +\gamma ^{3} = 12$
d.
does not have any solution
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q78 mcq
A hyperbola passes through the foci of the ellipse $\frac{x^{2}}{25} + \frac{y^{2}}{16} = 1$ and its transverse and conjugate axes coincide with major and minor axes of the ellipse, respectively. If the product of their eccentricities is one, then the equation of the hyperbola is:
a.
$\frac{x^{2}}{9} - \frac{y^{2}}{16} = 1$
b.
$x^{2} - y^{2} = 9$
c.
$\frac{x^{2}}{9} - \frac{y^{2}}{25} = 1$
d.
$\frac{x^{2}}{9} - \frac{y^{2}}{4} = 1$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q79 nat
Let $\vec{a}= ˆi +\alpha ˆj + 3ˆk$ and $\vec{b}= 3ˆi - \alpha ˆj + ˆk$ . If the area of the parallelogram whose adjacent sides are represented by the vectors $\vec{a}$ and $\vec{b}$ is $8\sqrt{3}$ square units, then $\vec{a}\cdot \vec{b}$ is equal to ___ .
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q80 mcq
The integral $\int \frac{e^{3 log}^{e}^{2}^{x}+5e^{2 log}^{e}^{2}^{x}}{e^{4 log}^{e x}+5e^{3 log}^{e x}-7e^{2 log}^{e x}} dx, \,x> 0$ , is equal to (where $c$ is a constant of integration)
a.
$log_{e} x^{2} + 5x-7 + c$
b.
$4 log_{e} x^{2} + 5x-7 + c$
c.
$\frac{1}{4}log_{e} x^{2}+ 5x-7 + c$
d.
$log_{e} \sqrt{x^{2}+ 5x-7}+c$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q81 mcq
A function $f(x)$ is given by $f(x) = \frac{5^{x}}{5^{x}+5}$ , then the sum of the series $f(\frac{1}{20})+f(\frac{2}{20})+f(\frac{3}{20})+ … +f( \frac{39}{20} )$ is equal to:
a.
$\frac{19}{2}$
b.
$\frac{49}{2}$
c.
$\frac{39}{2}$
d.
$\frac{29}{2}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q82 nat
If the curves $x=y^{4}$ and $xy=k$ cut at right angles, then $(4k)^{6}$ is equal to ___ .
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q83 mcq
Let $\alpha$ and $\beta$ be the roots of $x^{2} -6x-2 = 0$ . If $a_{n} =\alpha ^{n} - \beta ^{n}$ for $n⩾ 1$ , then the value of $\frac{a_{10}-2a_{8}}{3a_{9}}$ is:
a.
$1$
b.
$3$
c.
$2$
d.
$4$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q84 nat
The value of $\int _{-2}^{2} 3x^{2}-3x-6 dx$ is
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q85 mcq
If $0 <x,y<\pi$ and $cosx+ cosy-cos(x+y) = \frac{3}{2}$ , then $sinx+ cosy$ is equal to:
a.
$\frac{1}{2}$
b.
$\frac{\sqrt{3}}{2}$
c.
$\frac{1-\sqrt{3}}{2}$
d.
$\frac{1+\sqrt{3}}{2}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q86 mcq
$cosec[2 cot^{-1}(5) + cos^{-1}( \frac{4}{5})]$ is equal to:
a.
$\frac{65}{56}$
b.
$\frac{75}{56}$
c.
$\frac{65}{33}$
d.
$\frac{56}{33}$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q87 nat
If the curve, $y=y(x)$ represented by the solution of the differential equation $(2xy^{2} - y)dx+x dy= 0$ , passes through the intersection of the lines, $2x-3y= 1$ and $3x+ 2y= 8$ , then $|y(1)|$ is equal to ___ .
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q88 mcq
Let $x$ denote the total number of one-one functions from a set $A$ with $3$ elements to a set $B$ with $5$ elements and $y$ denote the total number of one-one functions from the set $A$ to the set $A\times B$ . Then :
a.
$y= 273x$
b.
$2y= 273x$
c.
$2y= 91x$
d.
$y= 91x$
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q89 nat
If the remainder when $x$ is divided by $4$ is $3$ , then the remainder when $(2020 +x)^{2022}$ is divided by $8$ is ___ .
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.

Q90 nat
$|| ||$ $||$ A line is a common tangent to the circle $(x-3)^{2} +y^{2} = 9$ and the parabola $y^{2} = 4x$ . If the two points of contact $(a,b)$ and $(c,d)$ are distinct and lie in the first quadrant, then $2(a+c)$ is equal to ___ .
Numerical answer locked.
Correct Answer & Step-by-Step Solution Locked

Sign in free to reveal the correct answer and AI explanation for this question.