JEE Main 2024 — 5 Apr Shift 2 (Previous Year Paper)

JEE Main · 2024 · with answers and explanations

questions
83
Total marks
272
Duration
180 minutes
Negative marking
−1

Subjects: Physics · Chemistry · Mathematics

Question 1

Physics · 4 marks · −1

A particle moves in x – y plane under the influence of a force F⃗\vec F such that its linear momentum is p⃗(t)=i^cos⁡(kt)−j^sin⁡(kt)\vec p(t)=\hat i\cos(kt)-\hat j\sin(kt). If k is constant, the angle between F⃗\vec F and p⃗\vec p will be :

  1. A.π4\frac\pi4
  2. B.π6\frac\pi6
  3. C.π2\frac\pi2
  4. D.π3\frac\pi3

Correct answer: C

Explanation: F⃗⋅p⃗=12ddt∣p⃗∣2=0\vec F\cdot\vec p=\frac12\frac{d}{dt}|\vec p|^2=0.

Question 2

Physics · 4 marks · −1

What is the dimensional formula of ab−1ab^{-1} in the equation (P+aV2)(V−b)=RT\left(P+\frac{a}{V^2}\right)(V-b)=RT, where letters have their usual meaning.

  1. A.[M−1L5T3][M^{-1}L^5T^3]
  2. B.[M6L7T4][M^6L^7T^4]
  3. C.[ML2T−2][ML^2T^{-2}]
  4. D.[M0L3T−2][M^0L^3T^{-2}]

Correct answer: C

Explanation: a/b∼PVa/b\sim PV: energy.

Question 3

Physics · 4 marks · −1

A man carrying a monkey on his shoulder does cycling smoothly on a circular track of radius 9 m and completes 120 revolutions in 3 minutes. The magnitude of centripetal acceleration of monkey is (in m/s²) :

  1. A.57600π257600\pi^2 m s−2^{-2}
  2. B.Zero
  3. C.4π24\pi^2 m s−2^{-2}
  4. D.16π216\pi^2 m s−2^{-2}

Correct answer: D

Explanation: ω=4π3\omega=\frac{4\pi}{3} rad/s; a=ω2r=16π2a=\omega^2r=16\pi^2.

Question 4

Physics · 4 marks · −1

A heavy box of mass 50 kg is moving on a horizontal surface. If co-efficient of kinetic friction between the box and horizontal surface is 0.3 then force of kinetic friction is :

  1. A.1.47 N
  2. B.147 N
  3. C.14.7 N
  4. D.1470 N

Correct answer: B

Question 5

Physics · 4 marks · −1

A body is moving unidirectionally under the influence of a constant power source. Its displacement in time t is proportional to :

  1. A.tt
  2. B.t3/2t^{3/2}
  3. C.t2t^2
  4. D.t2/3t^{2/3}

Correct answer: B

Explanation: v∝t1/2v\propto t^{1/2}, so s∝t3/2s\propto t^{3/2}.

Question 6

Physics · 4 marks · −1

A satellite revolving around a planet in stationary orbit has time period 6 hours. The mass of planet is one-fourth the mass of earth. The radius orbit of planet is : (Given = Radius of geo-stationary orbit for earth is 4.2×1044.2\times10^4 km)

  1. A.1.4×1041.4\times10^4 km
  2. B.1.05×1041.05\times10^4 km
  3. C.8.4×1048.4\times10^4 km
  4. D.1.68×1051.68\times10^5 km

Correct answer: B

Explanation: r3∝MT2r^3\propto MT^2: 14⋅116=164\frac14\cdot\frac1{16}=\frac1{64}, so r=4.2×1044r=\frac{4.2\times10^4}{4}.

Question 7

Physics · 4 marks · −1

Match List-I with List-II : List-I: (A) A force that restores an elastic body of unit area to its original state; (B) Two equal and opposite forces parallel to opposite faces; (C) Forces perpendicular everywhere to the surface per unit area same everywhere; (D) Two equal and opposite forces perpendicular to opposite faces List-II: (I) Bulk modulus; (II) Young's modulus; (III) Stress; (IV) Shear modulus Choose the correct answer from the options given below :

  1. A.(A)-(IV), (B)-(II), (C)-(III), (D)-(I)
  2. B.(A)-(III), (B)-(IV), (C)-(I), (D)-(II)
  3. C.(A)-(II), (B)-(IV), (C)-(I), (D)-(III)
  4. D.(A)-(III), (B)-(I), (C)-(II), (D)-(IV)

Correct answer: B

Question 8

Physics · 4 marks · −1

During an adiabatic process, if the pressure of a gas is found to be proportional to the cube of its absolute temperature, then the ratio of CPCV\frac{C_P}{C_V} for the gas is :

  1. A.53\frac53
  2. B.97\frac97
  3. C.32\frac32
  4. D.75\frac75

Correct answer: C

Explanation: γγ−1=3\frac{\gamma}{\gamma-1}=3.

Question 9

Physics · 4 marks · −1

If n is the number density and d is the diameter of the molecule, then the average distance covered by a molecule between two successive collisions (i.e. mean free path) is represented by :

  1. A.2nπd2\sqrt2n\pi d^2
  2. B.12nπd2\frac{1}{\sqrt{2n\pi d^2}}
  3. C.12nπd2\frac{1}{\sqrt2n\pi d^2}
  4. D.12n2π2d2\frac{1}{\sqrt2n^2\pi^2d^2}

Correct answer: C

Question 10

Physics · 4 marks · −1

The vehicles carrying inflammable fluids usually have metallic chains touching the ground :

  1. A.To protect tyres from catching dirt from ground
  2. B.To alert other vehicles
  3. C.It is a custom
  4. D.To conduct excess charge due to air friction to ground and prevent sparking

Correct answer: D

Question 11

Physics · 4 marks · −1

A galvanometer of resistance 100Ω when connected in series with 400Ω measures a voltage of upto 10 V. The value of resistance required to convert the galvanometer into ammeter to read upto 10 A is x×10−2x\times10^{-2} Ω. The value of x is :

  1. A.2
  2. B.800
  3. C.20
  4. D.200

Correct answer: C

Explanation: Ig=0.02I_g=0.02 A; S=0.02×1009.98≈0.2 ΩS=\frac{0.02\times100}{9.98}\approx0.2\ \Omega.

Question 12

Physics · 4 marks · −1

The ratio of heat dissipated per second through the resistance 5Ω and 10Ω in the circuit given below is :

Figure for question 12
  1. A.1 : 2
  2. B.2 : 1
  3. C.4 : 1
  4. D.1 : 1

Correct answer: B

Explanation: Parallel resistors: P∝1RP\propto\frac1R.

Question 13

Physics · 4 marks · −1

The electrostatic force (F⃗1)(\vec F_1) and magnetic force (F⃗2)(\vec F_2) acting on a charge q moving with velocity v can be written :

  1. A.F⃗1=qE⃗\vec F_1=q\vec E, F⃗2=q(V⃗×B⃗)\vec F_2=q(\vec V\times\vec B)
  2. B.F⃗1=qB⃗\vec F_1=q\vec B, F⃗2=q(B⃗×V⃗)\vec F_2=q(\vec B\times\vec V)
  3. C.F⃗1=qE⃗\vec F_1=q\vec E, F⃗2=q(B⃗×V⃗)\vec F_2=q(\vec B\times\vec V)
  4. D.F⃗1=qV⃗⋅E⃗\vec F_1=q\vec V\cdot\vec E, F⃗2=q(B⃗⋅V⃗)\vec F_2=q(\vec B\cdot\vec V)

Correct answer: A

Question 14

Physics · 4 marks · −1

A series LCR circuit is subjected to an ac signal of 200 V, 50 Hz. If the voltage across the inductor (L = 10 mH) is 31.4 V, then the current in this circuit is ______.

  1. A.68 A
  2. B.63 A
  3. C.10 A
  4. D.10 mA

Correct answer: C

Explanation: XL=3.14 ΩX_L=3.14\ \Omega.

Question 15

Physics · 4 marks · −1

Match List-I with List-II : List-I (EM-Wave): (A) Infra-red; (B) Ultraviolet; (C) X-rays; (D) Gamma rays. List-II (Wavelength Range): (I) <10−3<10^{-3} nm; (II) 400 nm to 1 nm; (III) 1 mm to 700 nm; (IV) 1 nm to 10−310^{-3} nm

  1. A.(A)-(III), (B)-(II), (C)-(IV), (D)-(I)
  2. B.(A)-(II), (B)-(I), (C)-(IV), (D)-(III)
  3. C.(A)-(IV), (B)-(III), (C)-(II), (D)-(I)
  4. D.(A)-(I), (B)-(III), (C)-(II), (D)-(IV)

Correct answer: A

Question 16

Physics · 4 marks · −1

Given below are two statements : Statement I : When the white light passed through a prism, the red light bends lesser than yellow and violet. Statement II : The refractive indices are different for different wavelengths in dispersive medium. In the light of the above statements, chose the correct answer from the options given below:

  1. A.Statement I is false but Statement II is true
  2. B.Statement I is true but Statement II is false
  3. C.Both Statement I and Statement II are true
  4. D.Both Statement I and Statement II are false

Correct answer: C

Question 17

Physics · 4 marks · −1

Which of the following statement is not true about stopping potential (V0)(V_0)?

  1. A.It is 1/e times the maximum kinetic energy of electrons emitted.
  2. B.It increases with increase in intensity of the incident light.
  3. C.It depends on the nature of emitter material.
  4. D.It depends upon frequency of the incident light.

Correct answer: B

Question 18

Physics · 4 marks · −1

The angular momentum of an electron in a hydrogen atom is proportional to : (Where r is the radius of orbit of electron)

  1. A.r
  2. B.r\sqrt r
  3. C.1r\frac1{\sqrt r}
  4. D.1r\frac1r

Correct answer: B

Explanation: L∝nL\propto n, r∝n2r\propto n^2.

Question 19

Physics · 4 marks · −1

The output (Y) of logic circuit given below is 0 only when :

Figure for question 19
  1. A.A = 1, B = 0
  2. B.A = 0, B = 1
  3. C.A = 0, B = 0
  4. D.A = 1, B = 1

Correct answer: C

Explanation: Y=(A+B)+B⋅1=A+BY=(A+B)+B\cdot1=A+B.

Question 20

Physics · 4 marks · −1

A vernier callipers has 20 divisions on the vernier scale, which coincides with 19th19^{th} division on the main scale. The least count of the instrument is 0.1 mm. One main scale division is equal to ______ mm.

  1. A.0.5
  2. B.2
  3. C.5
  4. D.1

Correct answer: B

Explanation: LC =MSD20=\frac{\text{MSD}}{20}.

Question 21

Physics · 4 marks · −1

The maximum height reached by a projectile is 64 m. If the initial velocity is halved, the new maximum height of the projectile is ______ m.

Correct answer: 16

Question 22

Physics · 4 marks · −1

A hollow sphere is rolling on a plane surface about its axis of symmetry. The ratio of rotational kinetic energy to its total kinetic energy is x5\frac x5. The value of x is ______.

Correct answer: 2

Explanation: 1/31+2/3=25\frac{1/3}{1+2/3}=\frac25.

Question 23

Physics · 4 marks · −1

A hydraulic press containing water has two arms with diameters as mentioned in the figure. A force of 10 N is applied on the surface of water in the thinner arm. The force required to be applied on the surface of water in the thicker arm to maintain equilibrium of water is ______ N.

Figure for question 23

Correct answer: 1000

Explanation: 10×100=100010\times100=1000 N.

Question 24

Physics · 4 marks · −1

A sonometer wire of resonating length 90 cm has a fundamental frequency of 400 Hz when kept under some tension. The resonating length of the wire with fundamental frequency of 600 Hz under same tension ______ cm.

Correct answer: 60

Question 25

Physics · 4 marks · −1

The electric field at point p due to an electric dipole is E. The electric field at point R on equitorial line will be Ex\frac Ex. The value of x :

Figure for question 25

Correct answer: 16

Explanation: EP=2kpr3E_P=\frac{2kp}{r^3}, ER=kp8r3=E16E_R=\frac{kp}{8r^3}=\frac{E}{16}.

Question 26

Physics · 4 marks · −1

A wire of resistance 20Ω is divided into 10 equal parts, resulting pairs. A combination of two parts are connected in parallel and so on. Now resulting pairs of parallel combination are connected in series. The equivalent resistance of final combination is ______ Ω.

Correct answer: 5

Explanation: Each part 2 Ω; pairs give 1 Ω; five in series.

Question 27

Physics · 4 marks · −1

A solenoid of length 0.5 m has a radius of 1 cm and is made up of 'm' number of turns. It carries a current of 5 A. If the magnitude of the magnetic field inside the solenoid is 6.28×10−36.28\times10^{-3} T then the value of m is ______.

Correct answer: 500

Explanation: m=BLμ0I=500m=\frac{BL}{\mu_0I}=500.

Question 28

Physics · 4 marks · −1

The current in an inductor is given by I = (3t + 8) where t is in second. The magnitude of induced emf produced in the inductor is 12 mV. The self-inductance of the inductor ______ mH.

Correct answer: 4

Question 29

Physics · 4 marks · −1

In a single slit experiment, a parallel beam of green light of wavelength 550 nm passes through a slit of width 0.20 mm. The transmitted light is collected on a screen 100 cm away. The distance of first order minima from the central maximum will be x×10−5x\times10^{-5} m. The value of x is :

Correct answer: 275

Explanation: λDa=2.75×10−3\frac{\lambda D}{a}=2.75\times10^{-3} m.

Question 30

Physics · 4 marks · −1

The shortest wavelength of the spectral lines in the Lyman series of hydrogen spectrum is 915 Å. The longest wavelength of spectral lines in the Balmer series will be ______ Å.

Correct answer: 6588

Explanation: λ=915×365=6588\lambda=915\times\frac{36}{5}=6588 Å.

Question 31

Chemistry · 4 marks · −1

The number of moles of methane required to produce 11 g CO2\text{CO}_2(g) after complete combustion is : (Given molar mass of methane in g mol−1^{-1} : 16)

  1. A.0.35
  2. B.0.5
  3. C.0.75
  4. D.0.25

Correct answer: D

Question 32

Chemistry · 4 marks · −1

Given below are two statements : Statement I : The metallic radius of Na is 1.86 Å and the ionic radius of Na+^+ is lesser than 1.86 Å. Statement II : Ions are always smaller in size than the corresponding elements. In the light of the above statements, choose the correct answer from the options given below :

  1. A.Both Statement I and Statement II are false
  2. B.Statement I is incorrect but Statement II is true
  3. C.Both Statement I and Statement II are true
  4. D.Statement I is correct but Statement II is false

Correct answer: D

Explanation: Anions are larger than their atoms.

Question 33

Chemistry · 4 marks · −1

Match List I with List II : List I: (A) ICl (B) ICl3\text{ICl}_3 (C) ClF5\text{ClF}_5 (D) IF7\text{IF}_7. List II: (I) T - shape (II) pyramidal (III) Pentagonal bipyramidal (IV) Linear. Choose the correct answer from the options given below :

  1. A.(A)-(IV), (B)-(I), (C)-(II), (D)-(III)
  2. B.(A)-(I), (B)-(IV), (C)-(III), (D)-(II)
  3. C.(A)-(IV), (B)-(III), (C)-(II), (D)-(I)
  4. D.(A)-(I), (B)-(III), (C)-(II), (D)-(IV)

Correct answer: A

Question 34

Chemistry · 4 marks · −1

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : NH3\text{NH}_3 and NF3\text{NF}_3 molecule have pyramidal shape with a lone pair of electrons on nitrogen atom. The resultant dipole moment of NH3\text{NH}_3 is greater than that of NF3\text{NF}_3. Reason (R) : In NH3\text{NH}_3, the orbital dipole due to lone pair is in the same direction as the resultant dipole moment of the N – H bonds. F is the most electronegative element. In the light of the above statements, choose the correct answer from the options given below :

  1. A.Both (A) and (R) are true and (R) is the correct explanation of (A)
  2. B.(A) is false but (R) is true
  3. C.Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
  4. D.(A) is true but (R) is false

Correct answer: A

Question 35

Chemistry · 4 marks · −1

The correct statements from the following are : (A) The decreasing order of atomic radii of group 13 elements is Tl > In > Ga > Al > B. (B) Down the group 13 electronegativity decreases from top to bottom. (C) Al dissolves in dil. HCl and liberates H2\text{H}_2 but conc. HNO3\text{HNO}_3 renders Al passive by forming a protective oxide layer on the surface. (D) All elements of group 13 exhibits highly stable +1 oxidation state. (E) Hybridisation of Al in [Al(H2O)6]3+[\text{Al(H}_2\text{O)}_6]^{3+} ion is sp3d2sp^3d^2. Choose the correct answer from the options given below :

  1. A.(A), (C) and (E) only
  2. B.(A) and (C) only
  3. C.(C) and (E) only
  4. D.(A), (B), (C) and (E) only

Correct answer: C

Explanation: Ga is smaller than Al; electronegativity does not fall regularly; +1 is stable only for Tl.

Question 36

Chemistry · 4 marks · −1

The correct nomenclature for the following compound is : CH2=CH-CH2-CH(OH)-CH2-CH(CHO)-COOH\text{CH}_2\text{=CH-CH}_2\text{-CH(OH)-CH}_2\text{-CH(CHO)-COOH}

  1. A.2-formyl-4-hydroxyhept-7-enoic acid
  2. B.2-formyl-4-hydroxyhept-6-enoic acid
  3. C.2-carboxy-4-hydroxyhept-7-enal
  4. D.2-carboxy-4-hydroxyhept-6-enal

Correct answer: B

Question 37

Chemistry · 4 marks · −1

Match List I with List II. List I (Pair of compounds): (A) n-propanol and Isopropanol (B) Methoxypropane and ethoxyethane (C) Propanone and propanal (D) Neopentane and Isopentane. List II (Isomerism): (I) Metamerism (II) Chain Isomerism (III) Position Isomerism (IV) Functional Isomerism

  1. A.(A)-(II), (B)-(I), (C)-(IV), (D)-(III)
  2. B.(A)-(III), (B)-(I), (C)-(II), (D)-(IV)
  3. C.(A)-(I), (B)-(III), (C)-(IV), (D)-(II)
  4. D.(A)-(III), (B)-(I), (C)-(IV), (D)-(II)

Correct answer: D

Question 38

Chemistry · 4 marks · −1

Identify A and B in the given chemical reaction sequence : Benzene + succinic anhydride →AlCl3\xrightarrow{\text{AlCl}_3} A →Zn-Hg/HCl\xrightarrow{\text{Zn-Hg/HCl}} B →H+\xrightarrow{\text{H}^+} α-tetralone

Figure for question 38
  1. A.A = naphthalene-1,4-dione type; B = tetralin-1,4-diol
  2. B.A = 3-phenylpropanoic acid; B = 3-phenylpropan-1-ol
  3. C.A = 4-oxo-4-phenylbutanoic acid; B = 4-phenylbutanoic acid
  4. D.A = 1,4-naphthoquinone; B = naphthalene

Correct answer: C

Explanation: Friedel–Crafts acylation, Clemmensen reduction, intramolecular acylation.

Question 39

Chemistry · 4 marks · −1

Consider the given chemical reaction : Cyclohexene →KMnO4−H2SO4, Heat\xrightarrow{\text{KMnO}_4-\text{H}_2\text{SO}_4,\ \text{Heat}} Product "A". Product "A" is :

  1. A.picric acid
  2. B.acetic acid
  3. C.adipic acid
  4. D.oxalic acid

Correct answer: C

Question 40

Chemistry · 4 marks · −1

The quantity of silver deposited when one coulomb charge is passed through AgNO3\text{AgNO}_3 solution :

  1. A.1 g of silver
  2. B.1 electrochemical equivalent of silver
  3. C.1 chemical equivalent of silver
  4. D.0.1 g atom of silver

Correct answer: B

Question 41

Chemistry · 4 marks · −1

For the electro chemical cell, If E(M2+/M)0=0.46E^0_{(M^{2+}/M)}=0.46 V and E(X/X2−)0=0.34E^0_{(X/X^{2-})}=0.34 V. Which of the following is correct?

  1. A.M+X→M2++X2−M+X\to M^{2+}+X^{2-} is a spontaneous reaction
  2. B.Ecell=0.80E_{cell}=0.80 V
  3. C.Ecell=−0.80E_{cell}=-0.80 V
  4. D.M2++X2−→M+XM^{2+}+X^{2-}\to M+X is a spontaneous reaction

Correct answer: D

Explanation: E∘=0.46−0.34=0.12E^\circ=0.46-0.34=0.12 V for reduction of M2+^{2+} by X2−^{2-}.

Question 42

Chemistry · 4 marks · −1

The number of ions from the following that have the ability to liberate hydrogen from a dilute acid is ______. Ti2+\text{Ti}^{2+}, Cr2+\text{Cr}^{2+} and V2+\text{V}^{2+}

  1. A.2
  2. B.3
  3. C.1
  4. D.0

Correct answer: B

Question 43

Chemistry · 4 marks · −1

While preparing crystals of Mohr's salt, dil H2SO4\text{H}_2\text{SO}_4 is added to a mixture of ferrous sulphate and ammonium sulphate, before dissolving this mixture in water, dil H2SO4\text{H}_2\text{SO}_4 is added here to :

  1. A.prevent the hydrolysis of ferrous sulphate
  2. B.prevent the hydrolysis of ammonium sulphate
  3. C.make the medium strongly acidic
  4. D.increase the rate of formation of crystals

Correct answer: A

Question 44

Chemistry · 4 marks · −1

The number of complexes from the following with no electrons in the t2t_2 orbital is TiCl4\text{TiCl}_4, [MnO4]−[\text{MnO}_4]^-, [FeO4]2−[\text{FeO}_4]^{2-}, [FeCl4]−[\text{FeCl}_4]^-, [CoCl4]2−[\text{CoCl}_4]^{2-}

  1. A.1
  2. B.4
  3. C.3
  4. D.2

Correct answer: C

Explanation: Tetrahedral: d0^0, d0^0 and d2^2 (Fe(VI), e2t20e^2t_2^0).

Question 45

Chemistry · 4 marks · −1

The metal atom present in the complex MABXL (where A, B, X and L are unidentate ligands and M is metal) involves sp3sp^3 hybridization. The number of geometrical isomers exhibited by the complex is:

  1. A.2
  2. B.0
  3. C.4
  4. D.3

Correct answer: B

Question 46

Chemistry · 4 marks · −1

Identify the major product in the following reaction. 1-Bromo-1-methylcyclopentane →O‾H, C2H5OH\xrightarrow{\overline{\text{O}}\text{H},\ \text{C}_2\text{H}_5\text{OH}} Major Product

  1. A.Methylenecyclopentane
  2. B.Methylcyclopentane
  3. C.1-Methylcyclopentene
  4. D.1-Bromocyclopentene

Correct answer: C

Question 47

Chemistry · 4 marks · −1

CH3CH2-OH→(i) Jone’s Reagent (ii) KMnO4 (iii) NaOH, CaO, Δ\text{CH}_3\text{CH}_2\text{-OH}\xrightarrow{\text{(i) Jone's Reagent (ii) KMnO}_4\ \text{(iii) NaOH, CaO, }\Delta} P. Consider the above reaction sequence and identify the major product P.

  1. A.Methoxymethane
  2. B.Methanoic acid
  3. C.Methanal
  4. D.Methane

Correct answer: D

Question 48

Chemistry · 4 marks · −1

Coagulation of egg, on heating is because of :

  1. A.The secondary structure of protein remains unchanged
  2. B.Denaturation of protein occurs
  3. C.Biological property of protein remains unchanged
  4. D.Breaking of the peptide linkage in the primary structure of protein occurs

Correct answer: B

Question 49

Chemistry · 4 marks · −1

In an atom, total number of electrons having quantum numbers n = 4, ∣ml∣=1|m_l|=1 and ms=−12m_s=-\frac12 is ______

Correct answer: 6

Explanation: Six orbitals (4p, 4d, 4f with ml=±1m_l=\pm1), one electron each.

Question 50

Chemistry · 4 marks · −1

Number of compounds from the following with zero dipole moment is ______. HF, H2\text{H}_2, H2S\text{H}_2\text{S}, CO2\text{CO}_2, NH3\text{NH}_3, BF3\text{BF}_3, CH4\text{CH}_4, CHCl3\text{CHCl}_3, SiF4\text{SiF}_4, H2O\text{H}_2\text{O}, BeF2\text{BeF}_2

Correct answer: 6

Question 51

Chemistry · 4 marks · −1

Combustion of 1 mole of benzene is expressed at C6H6(l)+152O2(g)→6CO2(g)+3H2O(l)\text{C}_6\text{H}_6(l)+\frac{15}{2}\text{O}_2(g)\to6\text{CO}_2(g)+3\text{H}_2\text{O}(l). The standard enthalpy of combustion of 2 mol of benzene is −'x' kJ. x = ______. Given: 1. standard Enthalpy of formation of 1 mol of C6H6(l)\text{C}_6\text{H}_6(l) is 48.5 kJ mol−1^{-1}. 2. Standard Enthalpy of formation of 1 mol of CO2(g)\text{CO}_2(g) is −393.5 kJ mol−1^{-1}. 3. Standard Enthalpy of formation of 1 mol of H2O(l)\text{H}_2\text{O}(l) is −286 kJ mol−1^{-1}.

Correct answer: 6535

Explanation: 2[6(−393.5)+3(−286)−48.5]=−65352[6(-393.5)+3(-286)-48.5]=-6535 kJ.

Question 52

Chemistry · 4 marks · −1

Using the given figure, the ratio of RfR_f values of sample A and sample C is x×10−2x\times10^{-2}. Value of x is ______

Figure for question 52

Correct answer: 50

Explanation: 510=0.5\frac{5}{10}=0.5.

Question 53

Chemistry · 4 marks · −1

Considering acetic acid dissociates in water, its dissociation constant is 6.25×10−56.25\times10^{-5}. If 5 mL of acetic acid is dissolved in 1 litre water, the solution will freeze at −x×10−2-x\times10^{-2}°C, provided pure water freezes at 0°C. x = ______. (Nearest integer) Given : (Kf)water=1.86(K_f)_{\text{water}}=1.86 K kg mol−1^{-1}, density of acetic acid is 1.2 g mL−1^{-1}, molar mass of water = 18 g mol−1^{-1}, molar mass of acetic acid = 60 g mol−1^{-1}, density of water = 1 g cm−3^{-3}. Acetic acid dissociates as CH3COOH⇌CH3COO−+H+\text{CH}_3\text{COOH}\rightleftharpoons\text{CH}_3\text{COO}^-+\text{H}^+

Correct answer: 19

Explanation: 0.1 mol; α=6.25×10−4=0.025\alpha=\sqrt{6.25\times10^{-4}}=0.025; ΔT=1.86×0.1×1.025≈0.19\Delta T=1.86\times0.1\times1.025\approx0.19.

Question 54

Chemistry · 4 marks · −1

Consider the following single step reaction in gas phase at constant temperature. 2A(g)+B(g)→C(g)2\text{A}_{(g)}+\text{B}_{(g)}\to\text{C}_{(g)}. The initial rate of the reaction is recorded as r1r_1 when the reaction starts with 1.5 atm pressure of A and 0.7 atm pressure of B. After some time, the rate r2r_2 is recorded when the pressure of C becomes 0.5 atm. The ratio r1:r2r_1:r_2 is ______ ×10−1\times10^{-1}. (Nearest integer)

Correct answer: 315

Explanation: 1.52×0.70.52×0.2=31.5\frac{1.5^2\times0.7}{0.5^2\times0.2}=31.5.

Question 55

Chemistry · 4 marks · −1

The fusion of chromite ore with sodium carbonate in the presence of air leads to the formation of products A and B along with the evolution of CO2\text{CO}_2. The sum of spin-only magnetic moment values of A and B is ______ B.M. (Nearest integer) [Given atomic number : C : 6, Na : 11, O : 8, Fe : 26, Cr : 24]

Correct answer: 6

Explanation: Na2CrO4\text{Na}_2\text{CrO}_4 (0) + Fe2O3\text{Fe}_2\text{O}_3 (5.92).

Question 56

Chemistry · 4 marks · −1

In the Claisen-Schmidt reaction to prepare 351 g of dibenzalacetone using 87 g of acetone, the amount of benzaldehyde required is ______ g. (Nearest integer)

Correct answer: 318

Explanation: 1.5 mol product needs 3 mol benzaldehyde.

Question 57

Chemistry · 4 marks · −1

The product (C) in the following sequence of reactions has ______ π bonds. Propylbenzene →KMnO4−KOH, Δ\xrightarrow{\text{KMnO}_4-\text{KOH},\ \Delta} (A) →H3O+\xrightarrow{\text{H}_3\text{O}^+} (B) →Br2/FeBr3\xrightarrow{\text{Br}_2/\text{FeBr}_3} (C)

Correct answer: 4

Explanation: C = 3-bromobenzoic acid: 3 ring π + 1 C=O.

Question 58

Chemistry · 4 marks · −1

X g of ethanamine was subjected to reaction with NaNO2\text{NaNO}_2/HCl followed by hydrolysis to liberate N2\text{N}_2 and HCl. The HCl generated was completely neutralised by 0.2 moles of NaOH. X is ______ g.

Correct answer: 9

Question 59

Mathematics · 4 marks · −1

60 words can be made using all the letters of the word BHBJO, with or without meaning. If these words are written as in a dictionary, then the 50th50^{th} word is :

  1. A.JBBOH
  2. B.OBBJH
  3. C.OBBHJ
  4. D.HBBJO

Correct answer: B

Explanation: B-words 24, H 12, J 12; then OBBHJ (49), OBBJH (50).

Question 60

Mathematics · 4 marks · −1

For x ⩾ 0, the least value of K, for which 41+x+41−x4^{1+x}+4^{1-x}, K2\frac K2, 16x+16−x16^x+16^{-x} are three consecutive terms of an A.P., is equal to :

  1. A.8
  2. B.4
  3. C.10
  4. D.16

Correct answer: C

Explanation: K=4(4x+4−x)+(16x+16−x)K=4(4^x+4^{-x})+(16^x+16^{-x}), minimum 10 at x=0x=0.

Question 61

Mathematics · 4 marks · −1

If the constant term in the expansion of (35x+2x53)12\left(\frac{\sqrt[5]3}{x}+\frac{2x}{\sqrt[3]5}\right)^{12}, x≠0x\ne0, is α×28×35\alpha\times2^8\times\sqrt[5]3, then 25α is equal to :

  1. A.724
  2. B.742
  3. C.639
  4. D.693

Correct answer: D

Explanation: r=6r=6: 12C6 36/5 26 5−2{}^{12}C_6\,3^{6/5}\,2^6\,5^{-2}; α=924×34×25\alpha=\frac{924\times3}{4\times25}, 25α=69325\alpha=693.

Question 62

Mathematics · 4 marks · −1

Let A(−1, 1) and B(2, 3) be two points and P be a variable point above the line AB such that the area of △PAB is 10. If the locus of P is ax + by = 15, then 5a + 2b is :

  1. A.6
  2. B.−65-\frac65
  3. C.4
  4. D.−125-\frac{12}{5}

Correct answer: D

Explanation: Locus 2x−3y+25=02x-3y+25=0, i.e. −65x+95y=15-\frac65x+\frac95y=15.

Question 63

Mathematics · 4 marks · −1

Let ABCD and AEFG be squares of side 4 and 2 units, respectively. The point E is on the line segment AB and the point F is on the diagonal AC. Then the radius r of the circle passing through the point F and touching the line segments BC and CD satisfies:

  1. A.r = 0
  2. B.2r2−4r+1=02r^2-4r+1=0
  3. C.2r2−8r+7=02r^2-8r+7=0
  4. D.r2−8r+8=0r^2-8r+8=0

Correct answer: D

Explanation: With C at the origin, centre (r,r)(r,r) and F=(2,2)F=(2,2): 2(2−r)2=r22(2-r)^2=r^2.

Question 64

Mathematics · 4 marks · −1

Let the circle C1:x2+y2−2(x+y)+1=0C_1:x^2+y^2-2(x+y)+1=0 and C2C_2 be a circle having centre at (−1, 0) and radius 2. If the line of the common chord of C1C_1 and C2C_2 intersects the y-axis at the point P, then the square of the distance of P from the centre of C1C_1 is :

  1. A.2
  2. B.1
  3. C.4
  4. D.6

Correct answer: A

Explanation: Common chord 4x+2y−4=04x+2y-4=0 meets the y-axis at (0, 2); distance² to (1, 1) is 2.

Question 65

Mathematics · 4 marks · −1

Let the set S = {2, 4, 8, 16, ..., 512} be partitioned into 3 sets A, B, C with equal number of elements such that A ∪ B ∪ C = S and A ∩ B = B ∩ C = A ∩ C = φ. The maximum number of such possible partitions of S is equal to:

  1. A.1680
  2. B.1640
  3. C.1520
  4. D.1710

Correct answer: A

Explanation: 9!3!3!3!\frac{9!}{3!3!3!} for labelled sets A, B, C.

Question 66

Mathematics · 4 marks · −1

The values of m, n, for which the system of equations x + y + z = 4, 2x + 5y + 5z = 17, x + 2y + mz = n has infinitely many solutions, satisfy the equation :

  1. A.m2+n2−mn=39m^2+n^2-mn=39
  2. B.m2+n2−m−n=46m^2+n^2-m-n=46
  3. C.m2+n2+m+n=64m^2+n^2+m+n=64
  4. D.m2+n2+mn=68m^2+n^2+mn=68

Correct answer: A

Explanation: Δ=3m−3=0⇒m=2\Delta=3m-3=0\Rightarrow m=2; consistency gives n=7n=7.

Question 67

Mathematics · 4 marks · −1

Let f,g:R→Rf,g:\mathbb{R}\to\mathbb{R} be defined as : f(x)=∣x−1∣f(x)=|x-1| and g(x)={ex,x≥0x+1,x≤0g(x)=\begin{cases}e^x, & x\ge0\\ x+1, & x\le0\end{cases}. Then the function f(g(x)) is

  1. A.neither one-one nor onto.
  2. B.one-one but not onto.
  3. C.onto but not one-one.
  4. D.both one-one and onto.

Correct answer: A

Explanation: f(g(x))≥0f(g(x))\ge0 and equals 1 at x=−1x=-1 and x=ln⁡2x=\ln2.

Question 68

Mathematics · 4 marks · −1

Let f:[−1,2]→Rf:[-1,2]\to\mathbb{R} be given by f(x)=2x2+x+[x2]−[x]f(x)=2x^2+x+[x^2]-[x], where [t] denotes the greatest integer less than or equal to t. The number of points, where f is not continuous, is :

  1. A.5
  2. B.6
  3. C.3
  4. D.4

Correct answer: D

Explanation: Candidates 0,1,2,3,20,1,\sqrt2,\sqrt3,2; at x=1x=1 the jumps of [x2][x^2] and [x][x] cancel.

Question 69

Mathematics · 4 marks · −1

Let β(m,n)=∫01xm−1(1−x)n−1dx\beta(m,n)=\int_0^1x^{m-1}(1-x)^{n-1}dx, m, n > 0. If ∫01(1−x10)20dx=a×β(b,c)\int_0^1(1-x^{10})^{20}dx=a\times\beta(b,c), then 100(a + b + c) equals

  1. A.1021
  2. B.2120
  3. C.2012
  4. D.1120

Correct answer: B

Explanation: x10=tx^{10}=t: 110β(110,21)\frac1{10}\beta\left(\frac1{10},21\right); 100(0.1+0.1+21)=2120100(0.1+0.1+21)=2120.

Question 70

Mathematics · 4 marks · −1

The area enclosed between the curves y = x|x| and y = x − |x| is :

  1. A.43\frac43
  2. B.1
  3. C.23\frac23
  4. D.83\frac83

Correct answer: A

Explanation: For x<0x<0: between −x2-x^2 and 2x2x on [−2,0][-2,0].

Question 71

Mathematics · 4 marks · −1

Consider three vectors a⃗,b⃗,c⃗\vec a,\vec b,\vec c. Let ∣a⃗∣=2|\vec a|=2, ∣b⃗∣=3|\vec b|=3 and a⃗=b⃗×c⃗\vec a=\vec b\times\vec c. If α∈[0,π3]\alpha\in\left[0,\frac\pi3\right] is the angle between the vectors b⃗\vec b and c⃗\vec c, then the minimum value of 27∣c⃗−a⃗∣227|\vec c-\vec a|^2 is equal to:

  1. A.110
  2. B.124
  3. C.121
  4. D.105

Correct answer: B

Explanation: ∣c⃗∣=23sin⁡α|\vec c|=\frac{2}{3\sin\alpha}, c⃗⊥a⃗\vec c\perp\vec a: 27(∣c⃗∣2+4)27(|\vec c|^2+4) is least at α=π3\alpha=\frac\pi3: 27(1627+4)=12427\left(\frac{16}{27}+4\right)=124.

Question 72

Mathematics · 4 marks · −1

Let (α, β, γ) be the image of the point (8, 5, 7) in the line x−12=y+13=z−25\frac{x-1}{2}=\frac{y+1}{3}=\frac{z-2}{5}. Then α + β + γ is equal to :

  1. A.16
  2. B.20
  3. C.14
  4. D.18

Correct answer: C

Explanation: Foot at t=1t=1: (3, 2, 7); image (−2, −1, 7).

Question 73

Mathematics · 4 marks · −1

The coefficients a, b, c in the quadratic equation ax2+bx+c=0ax^2+bx+c=0 are from the set {1, 2, 3, 4, 5, 6}. If the probability of this equation having one real root bigger than the other is p, then 216 p equals :

  1. A.57
  2. B.76
  3. C.38
  4. D.19

Correct answer: C

Explanation: Count of b2>4acb^2>4ac: 0+1+3+7+10+17=38 (b = 1…6).

Question 74

Mathematics · 4 marks · −1

The number of real solutions of the equation x|x + 5| + 2|x + 7| − 2 = 0 is ______

Correct answer: 3

Question 75

Mathematics · 4 marks · −1

If 1+3−223+5−2618+93−112363+49−206180+…1+\frac{\sqrt3-\sqrt2}{2\sqrt3}+\frac{5-2\sqrt6}{18}+\frac{9\sqrt3-11\sqrt2}{36\sqrt3}+\frac{49-20\sqrt6}{180}+\ldots upto ∞ =2+(ba+1)log⁡e(ab)=2+\left(\sqrt{\frac ba}+1\right)\log_e\left(\frac ab\right), where a and b are integers with gcd(a, b) = 1, then 11a + 18b is equal to ______

Correct answer: 76

Question 76

Mathematics · 4 marks · −1

The number of solutions of sin⁡2x+(2+2x−x2)sin⁡x−3(x−1)2=0\sin^2x+(2+2x-x^2)\sin x-3(x-1)^2=0, where −π ≤ x ≤ π, is ______

Correct answer: 2

Explanation: With s=sin⁡xs=\sin x, u=(x−1)2u=(x-1)^2: (s+3)(s−u)=0(s+3)(s-u)=0, so sin⁡x=(x−1)2\sin x=(x-1)^2, which has 2 solutions in [0,2][0,2].

Question 77

Mathematics · 4 marks · −1

Let a line perpendicular to the line 2x − y = 10 touch the parabola y2=4(x−9)y^2=4(x-9) at the point P. The distance of the point P from the centre of the circle x2+y2−14x−8y+56=0x^2+y^2-14x-8y+56=0 is ______

Correct answer: 10

Explanation: Slope −12-\frac12: tangent point (9+1m2,2m)=(13,−4)(9+\frac{1}{m^2},\frac2m)=(13,-4); centre (7, 4); distance 10.

Question 78

Mathematics · 4 marks · −1

Let a > 0 be a root of the equation 2x2+x−2=02x^2+x-2=0. If lim⁡x→1a16(1−cos⁡(2+x−2x2))(1−ax)2=α+β17\lim_{x\to\frac1a}\frac{16(1-\cos(2+x-2x^2))}{(1-ax)^2}=\alpha+\beta\sqrt{17}, where α, β ∈ Z, then α + β is equal to ______

Correct answer: 170

Question 79

Mathematics · 4 marks · −1

Let the mean and the standard deviation of the probability distribution | X | α | 1 | 0 | −3 | | P(X) | 13\frac13 | K | 16\frac16 | 14\frac14 | be μ and σ, respectively. If σ − μ = 2, then σ + μ is equal to ______

Correct answer: 5

Question 80

Mathematics · 4 marks · −1

Let the maximum and minimum values of (8x−x2−12−4)2+(x−7)2\left(\sqrt{8x-x^2-12}-4\right)^2+(x-7)^2, x∈Rx\in\mathbb{R} be M and m, respectively. Then M2−m2M^2-m^2 is equal to ______

Correct answer: 1600

Question 81

Mathematics · 4 marks · −1

If f(t)=∫0π2x dx1−cos⁡2tsin⁡2xf(t)=\int_0^\pi\frac{2x\,dx}{1-\cos^2t\sin^2x}, 0 < t < π, then the value of ∫0π/2π2dtf(t)\int_0^{\pi/2}\frac{\pi^2dt}{f(t)} equals ______

Correct answer: 1

Explanation: f(t)=π∫0πdx1−cos⁡2tsin⁡2x=π2∣sin⁡t∣f(t)=\pi\int_0^\pi\frac{dx}{1-\cos^2t\sin^2x}=\frac{\pi^2}{|\sin t|}; ∫0π/2sin⁡t dt=1\int_0^{\pi/2}\sin t\,dt=1.

Question 82

Mathematics · 4 marks · −1

Let y = y(x) be the solution of the differential equation dydx+2x(1+x2)2y=xe1(1+x2)\frac{dy}{dx}+\frac{2x}{(1+x^2)^2}y=xe^{\frac{1}{(1+x^2)}}; y(0) = 0. Then the area enclosed by the curve f(x)=y(x)e−1(1+x2)f(x)=y(x)e^{-\frac{1}{(1+x^2)}} and the line y − x = 4 is ______

Correct answer: 18

Explanation: IF e−1/(1+x2)e^{-1/(1+x^2)}: f(x)=x22f(x)=\frac{x^2}{2}; area between y=x22y=\frac{x^2}{2} and y=x+4y=x+4 over [−2,4][-2,4] is 18.

Question 83

Mathematics · 4 marks · −1

Let the point (−1, α, β) lie on the line of the shortest distance between the lines x+2−3=y−24=z−52\frac{x+2}{-3}=\frac{y-2}{4}=\frac{z-5}{2} and x+2−1=y+62=z−10\frac{x+2}{-1}=\frac{y+6}{2}=\frac{z-1}{0}. Then (α−β)2(\alpha-\beta)^2 is equal to ______

Correct answer: 25

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