JEE Main 2024 — 5 Apr Shift 1 (Previous Year Paper)

JEE Main · 2024 · with answers and explanations

questions
88
Total marks
292
Duration
180 minutes
Negative marking
−1

Subjects: Physics · Chemistry · Mathematics

Question 1

Physics · 4 marks · −1

The angle between vector Q⃗\vec Q and the resultant of (2Q⃗+2P⃗)(2\vec Q+2\vec P) and (2Q⃗−2P⃗)(2\vec Q-2\vec P) is :

  1. A.tan⁡−1(2Q⃗−2P⃗)2Q⃗+2P⃗\tan^{-1}\frac{(2\vec Q-2\vec P)}{2\vec Q+2\vec P}
  2. B.0∘0^\circ
  3. C.tan⁡−1(P/Q)\tan^{-1}(P/Q)
  4. D.tan⁡−1(2Q/P)\tan^{-1}(2Q/P)

Correct answer: B

Explanation: Resultant =4Q⃗=4\vec Q.

Question 2

Physics · 4 marks · −1

Time periods of oscillation of the same simple pendulum measured using four different measuring clocks were recorded as 4.62 s, 4.632 s, 4.6 s and 4.64 s. The arithmetic mean of these readings in correct significant figure is :

  1. A.5 s
  2. B.4.623 s
  3. C.4.6 s
  4. D.4.62 s

Correct answer: C

Explanation: Mean 4.623 s, rounded to the least precise reading (one decimal).

Question 3

Physics · 4 marks · −1

If G be the gravitational constant and u be the energy density then which of the following quantity have the dimensions as that of the uG\sqrt{uG} :

  1. A.pressure gradient per unit mass
  2. B.Gravitational potential
  3. C.Energy per unit mass
  4. D.Force per unit mass

Correct answer: D

Explanation: [uG]=[ML−1T−2][M−1L3T−2]=[L2T−4][uG]=[ML^{-1}T^{-2}][M^{-1}L^3T^{-2}]=[L^2T^{-4}], so uG\sqrt{uG} is an acceleration.

Question 4

Physics · 4 marks · −1

A wooden block of mass 5 kg rests on a soft horizontal floor. When an iron cylinder of mass 25 kg is placed on the top of the block, the floor yields and the block and the cylinder together go down with an acceleration of 0.1 m s−2^{-2}. The action force of the system on the floor is equal to:

  1. A.196 N
  2. B.291 N
  3. C.294 N
  4. D.297 N

Correct answer: B

Explanation: 30(9.8−0.1)=29130(9.8-0.1)=291 N.

Question 5

Physics · 4 marks · −1

A body of mass 50 kg is lifted to a height of 20 m from the ground in the two different ways as shown in the figures. The ratio of work done against the gravity in both the respective cases, will be :

Figure for question 5
  1. A.1 : 2
  2. B.3:2\sqrt3:2
  3. C.2 : 1
  4. D.1 : 1

Correct answer: D

Question 6

Physics · 4 marks · −1

Ratio of radius of gyration of a hollow sphere to that of a solid cylinder of equal mass, for moment of Inertia about their diameter axis AB as shown in figure is 8/x\sqrt{8/x}. The value of x is :

Figure for question 6
  1. A.51
  2. B.34
  3. C.17
  4. D.67

Correct answer: D

Explanation: Sphere: k2=23R2k^2=\frac23R^2; cylinder about a diameter of an end face: k2=R24+(4R)23=6712R2k^2=\frac{R^2}{4}+\frac{(4R)^2}{3}=\frac{67}{12}R^2; ratio2=867^2=\frac{8}{67}.

Question 7

Physics · 4 marks · −1

A simple pendulum doing small oscillations at a place R height above earth surface has time period of T1=4T_1=4 s. T2T_2 would be it's time period if it is brought to a point which is at a height 2R from earth surface. Choose the correct relation [R = radius of earth] :

  1. A.2T1=T22T_1=T_2
  2. B.2T1=3T22T_1=3T_2
  3. C.T1=T2T_1=T_2
  4. D.3T1=2T23T_1=2T_2

Correct answer: D

Explanation: T∝1g∝rT\propto\frac1{\sqrt g}\propto r: T1:T2=2:3T_1:T_2=2:3.

Question 8

Physics · 4 marks · −1

In hydrogen like system the ratio of coulombian force and gravitational force between an electron and a proton is in the order of :

  1. A.103910^{39}
  2. B.102910^{29}
  3. C.101910^{19}
  4. D.103610^{36}

Correct answer: A

Question 9

Physics · 4 marks · −1

Match List I with List II : List I: (A) Kinetic energy of planet; (B) Gravitation Potential energy of sun-planet system; (C) Total mechanical energy of planet; (D) Escape energy at the surface of planet for unit mass object List II: (I) −GMma-\frac{GMm}{a}; (II) GMm2a\frac{GMm}{2a}; (III) Gmr\frac{Gm}{r}; (IV) −GMm2a-\frac{GMm}{2a} (Where a = radius of planet orbit, r = radius of planet, M = mass of Sun, m = mass of planet) Choose the correct answer from the options given below :

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

Correct answer: B

Question 10

Physics · 4 marks · −1

Given below are two statements : Statement I : When a capillary tube is dipped into a liquid, the liquid neither rises nor falls in the capillary. The contact angle may be 0°. Statement II : The contact angle between a solid and a liquid is a property of the material of the solid and liquid as well. In the light of the above statement, choose the correct answer from the options given below.

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

Correct answer: C

Explanation: No rise or fall means a contact angle of 90°.

Question 11

Physics · 4 marks · −1

The heat absorbed by a system in going through the given cyclic process is :

Figure for question 11
  1. A.19.6 J
  2. B.61.6 J
  3. C.616 J
  4. D.431.2 J

Correct answer: B

Explanation: Heat = area of the circle =π(140)2=\pi(140)^2 cc·kPa =61575×10−3=61575\times10^{-3} J ≈ 61.6 J.

Question 12

Physics · 4 marks · −1

If the collision frequency of hydrogen molecules in a closed chamber at 27°C is Z, then the collision frequency of the same system at 127°C is :

  1. A.32Z\frac{\sqrt3}{2}Z
  2. B.23Z\frac{2}{\sqrt3}Z
  3. C.34Z\frac34Z
  4. D.43Z\frac43Z

Correct answer: B

Explanation: At fixed number density Z∝vˉ∝TZ\propto\bar v\propto\sqrt T.

Question 13

Physics · 4 marks · −1

In the given figure R1=10 ΩR_1=10\ \Omega, R2=8 ΩR_2=8\ \Omega, R3=4 ΩR_3=4\ \Omega and R4=8 ΩR_4=8\ \Omega. Battery is ideal with emf 12 V. Equivalent resistant of the circuit and current supplied by battery are respectively :

Figure for question 13
  1. A.10.5Ω and 1.14 A
  2. B.12Ω and 1 A
  3. C.10.5Ω and 1 A
  4. D.12Ω and 11.4 A

Correct answer: B

Explanation: 8∥8∥4=2 Ω8\parallel8\parallel4=2\ \Omega; total 12 Ω, 1 A.

Question 14

Physics · 4 marks · −1

In a co-axial straight cable, the central conductor and the outer conductor carry equal currents in opposite directions. The magnetic field is zero :

  1. A.outside the cable
  2. B.inside the outer conductor
  3. C.inside the inner conductor
  4. D.in between the two conductors

Correct answer: A

Question 15

Physics · 4 marks · −1

Two conducting circular loops A and B are placed in the same plane with their centers coinciding as shown in figure. The mutual inductance between them is :

Figure for question 15
  1. A.μ0πb22a\frac{\mu_0\pi b^2}{2a}
  2. B.μ02π⋅b2a\frac{\mu_0}{2\pi}\cdot\frac{b^2}{a}
  3. C.μ02π⋅a2b\frac{\mu_0}{2\pi}\cdot\frac{a^2}{b}
  4. D.μ0πa22b\frac{\mu_0\pi a^2}{2b}

Correct answer: D

Explanation: Field of B at the centre μ0I2b\frac{\mu_0I}{2b} threads area πa2\pi a^2.

Question 16

Physics · 4 marks · −1

An alternating voltage of amplitude 40 V and frequency 4 kHz is applied directly across the capacitor of 12 μF. The maximum displacement current between the plates of the capacitor is nearly :

  1. A.10 A
  2. B.12 A
  3. C.8 A
  4. D.13 A

Correct answer: B

Explanation: I=ωCV0=2π(4000)(12×10−6)(40)≈12I=\omega CV_0=2\pi(4000)(12\times10^{-6})(40)\approx12 A.

Question 17

Physics · 4 marks · −1

Light emerges out of a convex lens when a source of light kept at its focus. The shape of wavefront of the light is :

  1. A.both spherical and cylindrical
  2. B.plane
  3. C.spherical
  4. D.cylindrical

Correct answer: B

Question 18

Physics · 4 marks · −1

Given below are two statements : Statement I : Figure shows the variation of stopping potential with frequency (ν) for the two photosensitive materials M1M_1 and M2M_2. The slope gives value of he\frac he, where h is Planck's constant, e is the charge of electron. Statement II : M2M_2 will emit photoelectrons of greater kinetic energy for the incident radiation having same frequency. In the light of the above statements, choose the most appropriate answer from the options given below.

Figure for question 18
  1. A.Both Statement I and Statement II are correct
  2. B.Statement I is incorrect but Statement II is correct
  3. C.Both Statement I and Statement II are incorrect
  4. D.Statement I is correct and Statement II is incorrect

Correct answer: D

Explanation: Same slope h/eh/e; M2M_2 has the larger work function, so its electrons are less energetic.

Question 19

Physics · 4 marks · −1

An electron rotates in a circle around a nucleus having positive charge Ze. Correct relation between total energy (E) of electron to its potential energy (U) is :

  1. A.E = U
  2. B.2E = U
  3. C.2E = 3U
  4. D.E = 2U

Correct answer: B

Question 20

Physics · 4 marks · −1

Following gates section is connected in a complete suitable circuit. For which of the following combination, bulb will glow (ON) :

Figure for question 20
  1. A.A = 0, B = 0, C = 0, D = 1
  2. B.A = 0, B = 1, C = 1, D = 1
  3. C.A = 1, B = 0, C = 0, D = 0
  4. D.A = 1, B = 1, C = 1, D = 0

Correct answer: C

Explanation: For (3): Aˉ=0\bar A=0, B+C‾=1\overline{B+C}=1, NOR gives 0, while Dˉ=1\bar D=1 — different levels, bulb glows.

Question 21

Physics · 4 marks · −1

A body moves on a frictionless plane starting from rest. If SnS_n is distance moved between t = n − 1 and t = n and Sn−1S_{n-1} is distance moved between t = n − 2 and t = n − 1, then the ratio Sn−1Sn\frac{S_{n-1}}{S_n} is (1−2x)\left(1-\frac2x\right) for n = 10. The value of x is ______.

Correct answer: 19

Explanation: 1719=1−219\frac{17}{19}=1-\frac2{19}.

Question 22

Physics · 4 marks · −1

Three blocks M1M_1, M2M_2, M3M_3 having masses 4 kg, 6 kg and 10 kg respectively are hanging from a smooth pully using rope 1, 2 and 3 as shown in figure. The tension in the rope 1, T1T_1 when they are moving upward with acceleration of 2 m s−2^{-2} is ______ N (if g = 10 m/s²).

Figure for question 22

Correct answer: 240

Explanation: T1=20(10+2)=240T_1=20(10+2)=240 N.

Question 23

Physics · 4 marks · −1

The density and breaking stress of a wire are 6×1046\times10^4 kg/m³ and 1.2×1081.2\times10^8 N/m² respectively. The wire is suspended from a rigid support on a planet where acceleration due to gravity is 13\frac13rd of the value on the surface of earth. The maximum length of the wire with breaking is ______ m (take, g = 10 m/s²).

Correct answer: 600

Explanation: L=σρg/3=600L=\frac{\sigma}{\rho g/3}=600 m.

Question 24

Physics · 4 marks · −1

Three capacitors of capacitances 25 μF, 30 μF and 45 μF are connected in parallel to a supply of 100 V. Energy stored in the above combination is E. When these capacitors are connected in series to the same supply, the stored energy is 9xE\frac9xE. The value of x is ______.

Correct answer: 86

Explanation: Series capacitance 45043\frac{450}{43} μF vs parallel 100 μF: ratio 4.543=986\frac{4.5}{43}=\frac9{86}.

Question 25

Physics · 4 marks · −1

The electric field between the two parallel plates of a capacitor of 1.5 μF capacitance drops to one third of its initial value in 6.6 μs when the plates are connected by a thin wire. The resistance of this wire is ______ Ω. (Given, log 3 = 1.1)

Correct answer: 4

Explanation: t=RCln⁡3⇒R=6.61.5×1.1=4 Ωt=RC\ln3\Rightarrow R=\frac{6.6}{1.5\times1.1}=4\ \Omega.

Question 26

Physics · 4 marks · −1

In the experiment to determine the galvanometer resistance by half-deflection method, the plot of 1/θ1/\theta vs the resistance (R) of the resistance box is shown in the figure. The figure of merit of the galvanometer is ______ ×10−1\times10^{-1} A/division. [The source has emf 2V]

Figure for question 26

Correct answer: 5

Explanation: 1θ=k(R+G)E\frac1\theta=\frac{k(R+G)}{E}: slope kE=14⇒k=0.5\frac kE=\frac14\Rightarrow k=0.5 A/div.

Question 27

Physics · 4 marks · −1

A 2 A current carrying straight metal wire of resistance 1Ω, resistivity 2×10−62\times10^{-6} Ωm, area of cross-section 10 mm² and mass 500 g is suspended horizontally in mid air by applying a uniform magnetic field B⃗\vec B. The magnitude of B is ______ ×10−1\times10^{-1} T (given, g = 10 m/s²).

Correct answer: 5

Explanation: L=RAρ=5L=\frac{RA}{\rho}=5 m; B=mgIL=0.5B=\frac{mg}{IL}=0.5 T.

Question 28

Physics · 4 marks · −1

An ac source is connected in given series LCR circuit. The rms potential difference across the capacitor of 20 μF is ______ V.

Figure for question 28

Correct answer: 50

Explanation: XL=100X_L=100, XC=500X_C=500, Z=500 ΩZ=500\ \Omega; Irms=0.1I_{rms}=0.1 A; VC=50V_C=50 V.

Question 29

Physics · 4 marks · −1

In Young's double slit experiment, carried out with light of wavelength 5000 Å, the distance between the slits is 0.3 mm and the screen is at 200 cm from the slits. The central maximum is at x = 0 cm. The value of x for third maxima is ______ mm.

Correct answer: 10

Explanation: x=3λDd=10x=\frac{3\lambda D}{d}=10 mm.

Question 30

Physics · 4 marks · −1

If three helium nuclei combine to form a carbon nucleus then the energy released in this reaction is ______ ×10−2\times10^{-2} MeV. (Given 1u = 931 MeV/c², atomic mass of helium = 4.002603 u)

Correct answer: 727

Explanation: Δm=3(4.002603)−12=0.007809\Delta m=3(4.002603)-12=0.007809 u → 7.27 MeV.

Question 31

Chemistry · 4 marks · −1

An organic compound has 42.1% carbon, 6.4% hydrogen and remainder is oxygen. If its molecular weight is 342, then its molecular formula is :

  1. A.C11H18O12\text{C}_{11}\text{H}_{18}\text{O}_{12}
  2. B.C12H20O12\text{C}_{12}\text{H}_{20}\text{O}_{12}
  3. C.C12H22O11\text{C}_{12}\text{H}_{22}\text{O}_{11}
  4. D.C14H20O10\text{C}_{14}\text{H}_{20}\text{O}_{10}

Correct answer: C

Question 32

Chemistry · 4 marks · −1

The incorrect postulates of the Dalton's atomic theory are : (A) Atoms of different elements differ in mass. (B) Matter consists of divisible atoms. (C) Compounds are formed when atoms of different element combine in a fixed ratio. (D) All the atoms of given element have different properties including mass. (E) Chemical reactions involve reorganisation of atoms. Choose the correct answer from the options given below :

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

Correct answer: B

Question 33

Chemistry · 4 marks · −1

Given below are two statements : Statement I : In group 13, the stability of +1 oxidation state increases down the group. Statement II : The atomic size of gallium is greater than that of aluminium. In the light of the above statements, choose the most appropriate answer from the options given below :

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

Correct answer: D

Explanation: Ga (135 pm) is smaller than Al (143 pm).

Question 34

Chemistry · 4 marks · −1

The statement(s) that are correct about the species O2−\text{O}^{2-}, F−\text{F}^-, Na+\text{Na}^+ and Mg2+\text{Mg}^{2+}. (A) All are isoelectronic (B) All have the same nuclear charge (C) O2−\text{O}^{2-} has the largest ionic radii (D) Mg2+\text{Mg}^{2+} has the smallest ionic radii Choose the most appropriate answer from the options given below :

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

Correct answer: C

Question 35

Chemistry · 4 marks · −1

The following reaction occurs in the Blast furnance where iron ore is reduced to iron metal Fe2O3(s)+3CO(g)⇌Fe(l)+3CO2(g)\text{Fe}_2\text{O}_{3(s)}+3\text{CO}_{(g)}\rightleftharpoons\text{Fe}_{(l)}+3\text{CO}_{2(g)}. Using the Le-chatelier's principle, predict which one of the following will not disturb the equilibrium.

  1. A.Addition of CO2\text{CO}_2
  2. B.Removal of CO2\text{CO}_2
  3. C.Addition of Fe2O3\text{Fe}_2\text{O}_3
  4. D.Removal of CO

Correct answer: C

Explanation: Adding a pure solid does not change the reaction quotient.

Question 36

Chemistry · 4 marks · −1

The number of neutrons present in the more abundant isotope of boron is 'x'. Amorphous boron upon heating with air forms a product, in which the oxidation state of boron is 'y'. The value of x + y is ______

  1. A.3
  2. B.9
  3. C.4
  4. D.6

Correct answer: B

Explanation: 11^{11}B has 6 neutrons; B2_2O3_3 has B(+3).

Question 37

Chemistry · 4 marks · −1

Number of σ and π bonds present in ethylene molecule is respectively :

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

Correct answer: D

Question 38

Chemistry · 4 marks · −1

For the Compounds : (A) H3C-CH2-O-CH2-CH2-CH3\text{H}_3\text{C-CH}_2\text{-O-CH}_2\text{-CH}_2\text{-CH}_3 (B) H3C-CH2-CH2-CH2-CH3\text{H}_3\text{C-CH}_2\text{-CH}_2\text{-CH}_2\text{-CH}_3 (C) CH3-CH2-CO-CH2-CH3\text{CH}_3\text{-CH}_2\text{-CO-CH}_2\text{-CH}_3 (D) H3C-CH(OH)-CH2-CH2-CH3\text{H}_3\text{C-CH(OH)-CH}_2\text{-CH}_2\text{-CH}_3. The increasing order of boiling point is : Choose the correct answer from the options given below :

  1. A.(D) < (C) < (A) < (B)
  2. B.(B) < (A) < (C) < (D)
  3. C.(A) < (B) < (C) < (D)
  4. D.(B) < (A) < (D) < (C)

Correct answer: B

Explanation: Alkane < ether < ketone (dipolar) < alcohol (H-bonding).

Question 39

Chemistry · 4 marks · −1

Given below are two statements: Statement I : Nitration of benzene involves the following step - H-O+(H)-NO2⇌H2O+N+O2\text{H-}\overset{+}{\text{O}}(\text{H})\text{-NO}_2\rightleftharpoons\text{H}_2\text{O}+\overset{+}{\text{N}}\text{O}_2. Statement II : Use of Lewis base promotes the electrophilic substitution of benzene. In the light of the above statements, choose the most appropriate answer from the options given below :

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

Correct answer: A

Question 40

Chemistry · 4 marks · −1

The reaction at cathode in the cells commonly used in clocks involves.

  1. A.reduction of Mn from +7 to +2
  2. B.reduction of Mn from +4 to +3
  3. C.oxidation of Mn from +3 to +4
  4. D.oxidation of Mn from +2 to +7

Correct answer: B

Question 41

Chemistry · 4 marks · −1

Molar ionic conductivities of divalent cation and anion are 57 S cm² mol−1^{-1} and 73 S cm² mol−1^{-1} respectively. The molar conductivity of solution of an electrolyte with the above cation and anion will be :

  1. A.187 S cm² mol−1^{-1}
  2. B.260 S cm² mol−1^{-1}
  3. C.130 S cm² mol−1^{-1}
  4. D.65 S cm² mol−1^{-1}

Correct answer: C

Question 42

Chemistry · 4 marks · −1

The metal that shows highest and maximum number of oxidation state is :

  1. A.Fe
  2. B.Mn
  3. C.Co
  4. D.Ti

Correct answer: B

Question 43

Chemistry · 4 marks · −1

Which one of the following complexes will exhibit the least paramagnetic behaviour? [Atomic number, Cr = 24, Mn = 25, Fe = 26, Co = 27]

  1. A.[Cr(H2O)6]2+[\text{Cr(H}_2\text{O)}_6]^{2+}
  2. B.[Fe(H2O)6]2+[\text{Fe(H}_2\text{O)}_6]^{2+}
  3. C.[Co(H2O)6]2+[\text{Co(H}_2\text{O)}_6]^{2+}
  4. D.[Mn(H2O)6]2+[\text{Mn(H}_2\text{O)}_6]^{2+}

Correct answer: C

Explanation: Unpaired electrons 4, 4, 3, 5.

Question 44

Chemistry · 4 marks · −1

The correct order of ligands arranged in increasing field strength.

  1. A.F−^- < Br−^- < I−^- < NH3_3
  2. B.Br−^- < F−^- < H2_2O < NH3_3
  3. C.H2_2O < −-OH < CN−^- < NH3_3
  4. D.Cl−^- < −-OH < Br−^- < CN−^-

Correct answer: B

Question 45

Chemistry · 4 marks · −1

Given below are two statement: Statements I : Bromination of phenol in solvent with low polarity such as CHCl3\text{CHCl}_3 or CS2\text{CS}_2 requires Lewis acid catalyst. Statements II : The Lewis acid catalyst polarises the bromine to generate Br+^+. 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 true
  2. B.Statement I is true but Statement II is false
  3. C.Statement I is false but Statement II is true
  4. D.Both Statement I and Statement II are false

Correct answer: C

Question 46

Chemistry · 4 marks · −1

Identify compound (Z) in the following reaction sequence. Chlorobenzene + NaOH →623 K, 300 atm\xrightarrow{623\text{ K},\ 300\text{ atm}} X →HCl\xrightarrow{\text{HCl}} Y →Conc. HNO3\xrightarrow{\text{Conc. HNO}_3} Z

  1. A.2,4,6-Trinitrophenol (picric acid)
  2. B.2,4-Dinitrophenol
  3. C.2-Nitrophenol
  4. D.4-Nitrophenol

Correct answer: A

Explanation: Dow process to phenol, then nitration with concentrated nitric acid gives picric acid.

Question 47

Chemistry · 4 marks · −1

Identify 'A' in the following reaction: Butan-2-one →(i) N2H4 (ii) ethylene glycol/KOH\xrightarrow{\text{(i) N}_2\text{H}_4\ \text{(ii) ethylene glycol/KOH}} 'A'

  1. A.Butan-2-ol
  2. B.Acetone hydrazone ((CH3)2C=N-NH2(\text{CH}_3)_2\text{C=N-NH}_2)
  3. C.Butan-2-one hydrazone
  4. D.n-Butane

Correct answer: D

Question 48

Chemistry · 4 marks · −1

Which of the following gives a positive test with ninhydrin?

  1. A.Starch
  2. B.Egg albumin
  3. C.Polyvinyl chloride
  4. D.Cellulose

Correct answer: B

Question 49

Chemistry · 4 marks · −1

9.3 g of pure aniline is treated with bromine water at room temperature to give a white precipitate of the product 'P'. The mass of product 'P' obtaind is 26.4 g. The percentage yield is ______ %.

Correct answer: 80

Explanation: 0.1 mol 2,4,6-tribromoaniline = 33 g; 26.433=80%\frac{26.4}{33}=80\%.

Question 50

Chemistry · 4 marks · −1

The value of Rydberg constant (RH)(R_H) is 2.18×10−182.18\times10^{-18} J. The velocity of electron having mass 9.1×10−319.1\times10^{-31} kg in Bohr's first orbit of hydrogen atom = ______ ×105\times10^5 m s−1^{-1} (nearest integer).

Correct answer: 22

Explanation: v=2E/m=4.36×10−189.1×10−31≈2.19×106v=\sqrt{2E/m}=\sqrt{\frac{4.36\times10^{-18}}{9.1\times10^{-31}}}\approx2.19\times10^6 m/s.

Question 51

Chemistry · 4 marks · −1

In the lewis dot structure for NO2−\text{NO}_2^-, total number of valence electrons around nitrogen is ______

Correct answer: 8

Question 52

Chemistry · 4 marks · −1

The heat of combustion of solid benzoic acid at constant volume is −321.30 kJ at 27°C. The heat of combustion at constant pressure is (−321.30 − x R) kJ, the value of x is ______.

Correct answer: 150

Explanation: Δng=7−7.5=−0.5\Delta n_g=7-7.5=-0.5; ΔH=ΔU−0.5×300R=ΔU−150R\Delta H=\Delta U-0.5\times300R=\Delta U-150R (with R in the units of the problem).

Question 53

Chemistry · 4 marks · −1

An artificial cell is made by encapsulating 0.2M glucose solution within a semipermeable membrane. The osmotic pressure developed when the artificial cell is placed within a 0.05M solution of NaCl at 300 K is ______ ×10−1\times10^{-1} bar. (nearest integer). [Given : R = 0.083 L bar mol−1^{-1} K−1^{-1}] Assume complete dissociation of NaCl

Correct answer: 25

Explanation: Net concentration difference 0.2−0.1=0.10.2-0.1=0.1 M; π=0.1×0.083×300=2.49\pi=0.1\times0.083\times300=2.49 bar.

Question 54

Chemistry · 4 marks · −1

During Kinetic study of reaction 2A + B → C + D, the following results were obtained : | | A [M] | B [M] | initial rate of formation of D | | I | 0.1 | 0.1 | 6.0×10−36.0\times10^{-3} | | II | 0.3 | 0.2 | 7.20×10−27.20\times10^{-2} | | III | 0.3 | 0.4 | 2.88×10−12.88\times10^{-1} | | IV | 0.4 | 0.1 | 2.40×10−22.40\times10^{-2} | Based on above data, overall order of the reaction is ______

Correct answer: 3

Explanation: First order in A (I→IV), second order in B (II→III).

Question 55

Chemistry · 4 marks · −1

The spin-only magnetic moment value of the ion among Ti2+\text{Ti}^{2+}, V2+\text{V}^{2+}, Co3+\text{Co}^{3+} and Cr2+\text{Cr}^{2+}, that acts as strong oxidising agent in aqueous solution is ______ BM (Near integer). (Given atomic numbers : Ti : 22, V : 23, Cr : 24, Co : 27)

Correct answer: 5

Question 56

Chemistry · 4 marks · −1

The number of halobenzenes from the following that can be prepared by Sandmeyer's reaction is ______ (I) fluorobenzene (II) chlorobenzene (III) bromobenzene (IV) iodobenzene (V) astatobenzene

Correct answer: 2

Explanation: Only chloro- and bromobenzene.

Question 57

Chemistry · 4 marks · −1

Consider the given chemical reaction sequence : Phenol →Conc. H2SO4\xrightarrow{\text{Conc. H}_2\text{SO}_4} Product A →Conc. HNO3\xrightarrow{\text{Conc. HNO}_3} Product B. Total sum of oxygen atoms in Product A and Product B are ______

Correct answer: 14

Explanation: A = phenol-2,4-disulphonic acid (7 O), B = picric acid (7 O).

Question 58

Chemistry · 4 marks · −1

In a borax bead test under hot condition, a metal salt (one from the given) is heated at point B of the flame, resulted in green colour salt bead. The spin-only magnetic moment value of the salt is ______ BM (Nearest integer) [Given atomic number of Cu = 29, Ni = 28, Mn = 25, Fe = 26]

Figure for question 58

Correct answer: 6

Question 59

Mathematics · 4 marks · −1

Consider the following two statements : Statement I : For any two non-zero complex numbers z1,z2z_1,z_2, (∣z1∣+∣z2∣)∣z1∣z1∣+z2∣z2∣∣≤2(∣z1∣+∣z2∣)(|z_1|+|z_2|)\left|\frac{z_1}{|z_1|}+\frac{z_2}{|z_2|}\right|\le2(|z_1|+|z_2|), and Statement II : If x, y, z are three distinct complex numbers and a, b, c are three positive real numbers such that a∣y−z∣=b∣z−x∣=c∣x−y∣\frac{a}{|y-z|}=\frac{b}{|z-x|}=\frac{c}{|x-y|}, then a2y−z+b2z−x+c2x−y=1\frac{a^2}{y-z}+\frac{b^2}{z-x}+\frac{c^2}{x-y}=1. Between the above two statements,

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

Correct answer: A

Explanation: I holds since the unit-vector sum has modulus at most 2; II fails (the sum is 0, not 1).

Question 60

Mathematics · 4 marks · −1

If 11+2+12+3+…+199+100=m\frac1{\sqrt1+\sqrt2}+\frac1{\sqrt2+\sqrt3}+\ldots+\frac1{\sqrt{99}+\sqrt{100}}=m and 11⋅2+12⋅3+…+199⋅100=n\frac1{1\cdot2}+\frac1{2\cdot3}+\ldots+\frac1{99\cdot100}=n, then the point (m, n) lies on the line

  1. A.11(x−1)−100(y−2)=011(x-1)-100(y-2)=0
  2. B.11x−100y=011x-100y=0
  3. C.11(x−2)−100(y−1)=011(x-2)-100(y-1)=0
  4. D.11(x−1)−100y=011(x-1)-100y=0

Correct answer: B

Explanation: m=9m=9, n=99100n=\frac{99}{100}.

Question 61

Mathematics · 4 marks · −1

Suppose θ∈[0,π4]\theta\in\left[0,\frac\pi4\right] is a solution of 4cos⁡θ−3sin⁡θ=14\cos\theta-3\sin\theta=1. Then cos⁡θ\cos\theta is equal to :

  1. A.4(36+2)\frac{4}{(3\sqrt6+2)}
  2. B.6+6(36+2)\frac{6+\sqrt6}{(3\sqrt6+2)}
  3. C.4(36−2)\frac{4}{(3\sqrt6-2)}
  4. D.6−6(36−2)\frac{6-\sqrt6}{(3\sqrt6-2)}

Correct answer: C

Explanation: cos⁡θ=4+6625=436−2\cos\theta=\frac{4+6\sqrt6}{25}=\frac4{3\sqrt6-2}.

Question 62

Mathematics · 4 marks · −1

Let two straight lines drawn from the origin O intersect the line 3x + 4y = 12 at the points P and Q such that △OPQ is an isosceles triangle and ∠POQ = 90°. If l=OP2+PQ2+QO2l=OP^2+PQ^2+QO^2, then the greatest integer less than or equal to l is :

  1. A.42
  2. B.46
  3. C.44
  4. D.48

Correct answer: B

Explanation: Altitude h=125h=\frac{12}{5}; l=8h2=46.08l=8h^2=46.08.

Question 63

Mathematics · 4 marks · −1

If A(1, −1, 2), B(5, 7, −6), C(3, 4, −10) and D(−1, −4, −2) are the vertices of a quadrilateral ABCD, then its area is :

  1. A.48748\sqrt7
  2. B.122912\sqrt{29}
  3. C.24724\sqrt7
  4. D.242924\sqrt{29}

Correct answer: B

Explanation: 12∣AC⃗×BD⃗∣=12∣(−112,64,8)∣=1229\frac12|\vec{AC}\times\vec{BD}|=\frac12|(-112,64,8)|=12\sqrt{29}.

Question 64

Mathematics · 4 marks · −1

Let a circle C of radius 1 and closer to the origin be such that the lines passing through the point (3, 2) and parallel to the coordinate axes touch it. Then the shortest distance of the circle C from the point (5, 5) is :

  1. A.222\sqrt2
  2. B.424\sqrt2
  3. C.4
  4. D.5

Correct answer: C

Explanation: Centre (2, 1); distance to (5, 5) is 5, minus radius 1.

Question 65

Mathematics · 4 marks · −1

Let the line 2x + 3y − k = 0, k > 0, intersect the x-axis and y-axis at the points A and B, respectively. If the equation of the circle having the line segment AB as a diameter is x2+y2−3x−2y=0x^2+y^2-3x-2y=0 and the length of the latus rectum of the ellipse x2+9y2=k2x^2+9y^2=k^2 is mn\frac mn, where m and n are coprime, then 2m + n is equal to

  1. A.11
  2. B.10
  3. C.12
  4. D.13

Correct answer: A

Explanation: k=6k=6; ellipse x236+y24=1\frac{x^2}{36}+\frac{y^2}{4}=1 has latus rectum 43\frac43.

Question 66

Mathematics · 4 marks · −1

Let A and B be two square matrices of order 3 such that |A| = 3 and |B| = 2. Then ∣ATA(adj(2A))−1(adj(4B))(adj(AB))−1AAT∣\left|A^TA(\text{adj}(2A))^{-1}(\text{adj}(4B))(\text{adj}(AB))^{-1}AA^T\right| is equal to :

  1. A.108
  2. B.32
  3. C.81
  4. D.64

Correct answer: D

Explanation: 3⋅3⋅1576⋅16384⋅136⋅9=643\cdot3\cdot\frac1{576}\cdot16384\cdot\frac1{36}\cdot9=64.

Question 67

Mathematics · 4 marks · −1

If the system of equations 11x+y+λz=−511x+y+\lambda z=-5, 2x+3y+5z=32x+3y+5z=3, 8x−19y−39z=μ8x-19y-39z=\mu has infinitely many solutions, then λ4−μ\lambda^4-\mu is equal to :

  1. A.51
  2. B.45
  3. C.47
  4. D.49

Correct answer: C

Explanation: Δ=−124−62λ=0⇒λ=−2\Delta=-124-62\lambda=0\Rightarrow\lambda=-2; R3=2R1−7R2R_3=2R_1-7R_2 gives μ=−31\mu=-31.

Question 68

Mathematics · 4 marks · −1

Let A = {1, 3, 7, 9, 11} and B = {2, 4, 5, 7, 8, 10, 12}. Then the total number of one-one maps f : A → B, such that f(1) + f(3) = 14, is :

  1. A.480
  2. B.240
  3. C.120
  4. D.180

Correct answer: B

Explanation: 4 ordered choices for (f(1), f(3)), then 5⋅4⋅35\cdot4\cdot3.

Question 69

Mathematics · 4 marks · −1

Let f(x)=x5+2x3+3x+1f(x)=x^5+2x^3+3x+1, x∈Rx\in\mathbb{R}, and g(x) be a function such that g(f(x)) = x for all x∈Rx\in\mathbb{R}. Then g(7)g′(7)\frac{g(7)}{g'(7)} is equal to :

  1. A.14
  2. B.42
  3. C.7
  4. D.1

Correct answer: A

Explanation: f(1)=7f(1)=7, f′(1)=14f'(1)=14.

Question 70

Mathematics · 4 marks · −1

If the function f(x)=sin⁡3x+αsin⁡x−βcos⁡3xx3f(x)=\frac{\sin3x+\alpha\sin x-\beta\cos3x}{x^3}, x∈Rx\in\mathbb{R}, is continuous at x = 0, then f(0) is equal to :

  1. A.2
  2. B.−2
  3. C.4
  4. D.−4

Correct answer: D

Explanation: β=0\beta=0, α=−3\alpha=-3; the x3x^3 coefficient is −92+12=−4-\frac92+\frac12=-4.

Question 71

Mathematics · 4 marks · −1

Let a rectangle ABCD of sides 2 and 4 be inscribed in another rectangle PQRS such that the vertices of the rectangle ABCD lie on the sides of the rectangle PQRS. Let a and b be the sides of the rectangle PQRS when its area is maximum. Then (a+b)2(a+b)^2 is equal to :

  1. A.72
  2. B.60
  3. C.64
  4. D.80

Correct answer: A

Explanation: At θ = 45°: a=b=32a=b=3\sqrt2.

Question 72

Mathematics · 4 marks · −1

For the function f(x)=sin⁡x+3x−2π(x2+x)f(x)=\sin x+3x-\frac2\pi(x^2+x), where x∈[0,π2]x\in\left[0,\frac\pi2\right], consider the following two statements : (I) f is increasing in (0,π2)\left(0,\frac\pi2\right). (II) f′ is decreasing in (0,π2)\left(0,\frac\pi2\right). Between the above two statements,

  1. A.only (II) is true.
  2. B.only (I) is true.
  3. C.neither (I) nor (II) is true.
  4. D.both (I) and (II) are true

Correct answer: D

Explanation: f′′=−sin⁡x−4π<0f''=-\sin x-\frac4\pi<0 and f′(π2)=1−2π>0f'(\frac\pi2)=1-\frac2\pi>0.

Question 73

Mathematics · 4 marks · −1

The value of ∫−ππ2y(1+sin⁡y)1+cos⁡2ydy\int_{-\pi}^{\pi}\frac{2y(1+\sin y)}{1+\cos^2y}dy is :

  1. A.2π22\pi^2
  2. B.π22\frac{\pi^2}{2}
  3. C.π2\frac\pi2
  4. D.π2\pi^2

Correct answer: D

Explanation: Odd part vanishes; 4∫0πysin⁡y1+cos⁡2ydy=4⋅π2⋅π24\int_0^\pi\frac{y\sin y}{1+\cos^2y}dy=4\cdot\frac\pi2\cdot\frac\pi2.

Question 74

Mathematics · 4 marks · −1

The integral ∫0π/4136sin⁡x3sin⁡x+5cos⁡xdx\int_0^{\pi/4}\frac{136\sin x}{3\sin x+5\cos x}dx is equal to :

  1. A.3π−50log⁡e2+20log⁡e53\pi-50\log_e2+20\log_e5
  2. B.3π−25log⁡e2+10log⁡e53\pi-25\log_e2+10\log_e5
  3. C.3π−10log⁡e(22)+10log⁡e53\pi-10\log_e(2\sqrt2)+10\log_e5
  4. D.3π−30log⁡e2+20log⁡e53\pi-30\log_e2+20\log_e5

Correct answer: A

Explanation: sin⁡x=334(3sin⁡x+5cos⁡x)−534(3cos⁡x−5sin⁡x)\sin x=\frac3{34}(3\sin x+5\cos x)-\frac5{34}(3\cos x-5\sin x).

Question 75

Mathematics · 4 marks · −1

If y = y(x) is the solution of the differential equation dydx+2y=sin⁡(2x)\frac{dy}{dx}+2y=\sin(2x), y(0)=34y(0)=\frac34, then y(π8)y\left(\frac\pi8\right) is equal to:

  1. A.eπ/8e^{\pi/8}
  2. B.eπ/4e^{\pi/4}
  3. C.e−π/4e^{-\pi/4}
  4. D.e−π/8e^{-\pi/8}

Correct answer: C

Explanation: y=e−2x+sin⁡2x−cos⁡2x4y=e^{-2x}+\frac{\sin2x-\cos2x}{4}.

Question 76

Mathematics · 4 marks · −1

If the line 2−x3=3y−24λ+1=4−z\frac{2-x}{3}=\frac{3y-2}{4\lambda+1}=4-z makes a right angle with the line x+33μ=1−2y6=5−z7\frac{x+3}{3\mu}=\frac{1-2y}{6}=\frac{5-z}{7}, then 4λ+9μ4\lambda+9\mu is equal to :

  1. A.4
  2. B.13
  3. C.5
  4. D.6

Correct answer: D

Explanation: Directions (−3,4λ+13,−1)(-3,\frac{4\lambda+1}{3},-1) and (3μ,−3,−7)(3\mu,-3,-7): −9μ−(4λ+1)+7=0-9\mu-(4\lambda+1)+7=0.

Question 77

Mathematics · 4 marks · −1

Let d be the distance of the point of intersection of the lines x+63=y2=z+11\frac{x+6}{3}=\frac y2=\frac{z+1}{1} and x−74=y−93=z−42\frac{x-7}{4}=\frac{y-9}{3}=\frac{z-4}{2} from the point (7, 8, 9). Then d2+6d^2+6 is equal to :

  1. A.69
  2. B.78
  3. C.72
  4. D.75

Correct answer: D

Explanation: Intersection (3, 6, 2); d2=69d^2=69.

Question 78

Mathematics · 4 marks · −1

The coefficients a, b, c in the quadratic equation ax2+bx+c=0ax^2+bx+c=0 are chosen from the set {1, 2, 3, 4, 5, 6, 7, 8}. The probability of this equation having repeated roots is :

  1. A.1128\frac1{128}
  2. B.164\frac1{64}
  3. C.3256\frac3{256}
  4. D.3128\frac3{128}

Correct answer: B

Explanation: b2=4acb^2=4ac has 8 solutions out of 512.

Question 79

Mathematics · 4 marks · −1

The number of ways of getting a sum 16 on throwing a dice four times is ______

Correct answer: 125

Explanation: (153)−4(93)+6(33)=125\binom{15}{3}-4\binom93+6\binom33=125.

Question 80

Mathematics · 4 marks · −1

Let a1,a2,a3,…a_1,a_2,a_3,\ldots be in an arithmetic progression of positive terms. Let Ak=a12−a22+a32−a42+…+a2k−12−a2k2A_k=a_1^2-a_2^2+a_3^2-a_4^2+\ldots+a_{2k-1}^2-a_{2k}^2. If A3=−153A_3=-153, A5=−435A_5=-435 and a12+a22+a32=66a_1^2+a_2^2+a_3^2=66, then a17−A7a_{17}-A_7 is equal to ______

Correct answer: 910

Explanation: Ak=−dS2kA_k=-dS_{2k} gives d=3d=3, a1=1a_1=1; a17=49a_{17}=49, A7=−861A_7=-861.

Question 81

Mathematics · 4 marks · −1

If the constant term in the expansion of (1+2x−3x3)(32x2−13x)9(1+2x-3x^3)\left(\frac32x^2-\frac1{3x}\right)^9 is p, then 108p is equal to

Correct answer: 54

Explanation: 718+(−3)(−127)=12\frac7{18}+(-3)\left(-\frac1{27}\right)=\frac12.

Question 82

Mathematics · 4 marks · −1

Suppose AB is a focal chord of the parabola y2=12xy^2=12x of length l and slope m<3m<\sqrt3. If the distance of the chord AB from the origin is d, then ld2ld^2 is equal to _______

Correct answer: 108

Explanation: l=12cosec⁡2θl=12\operatorname{cosec}^2\theta, d=3sin⁡θd=3\sin\theta.

Question 83

Mathematics · 4 marks · −1

Let f be a differentiable function in the interval (0, ∞) such that f(1) = 1 and lim⁡t→xt2f(x)−x2f(t)t−x=1\lim_{t\to x}\frac{t^2f(x)-x^2f(t)}{t-x}=1 for each x > 0. Then 2f(2) + 3f(3) is equal to _______

Correct answer: 24

Explanation: 2xf(x)−x2f′(x)=12xf(x)-x^2f'(x)=1 gives f(x)=13x+2x23f(x)=\frac1{3x}+\frac{2x^2}{3}.

Question 84

Mathematics · 4 marks · −1

From a lot of 10 items, which include 3 defective items, a sample of 5 items is drawn at random. Let the random variable X denote the number of defective items in the sample. If the variance of X is σ2\sigma^2, then 96σ296\sigma^2 is equal to ______

Correct answer: 56

Explanation: Hypergeometric: σ2=5⋅310⋅710⋅59=712\sigma^2=5\cdot\frac3{10}\cdot\frac7{10}\cdot\frac59=\frac7{12}.

Question 85

Mathematics · 4 marks · −1

The number of distinct real roots of the equation |x||x + 2| − 5|x + 1| − 1 = 0 is _______

Correct answer: 3

Explanation: With u=x+1u=x+1: ∣u2−1∣−5∣u∣−1=0|u^2-1|-5|u|-1=0 has roots u=0u=0 and ∣u∣=5+332|u|=\frac{5+\sqrt{33}}{2}.

Question 86

Mathematics · 4 marks · −1

If S={a∈R:∣2a−1∣=3[a]+2{a}}S=\{a\in\mathbb{R}:|2a-1|=3[a]+2\{a\}\}, where [t] denotes the greatest integer less than or equal to t and {t} represents the fractional part of t, then 72∑a∈Sa72\sum_{a\in S}a is equal to ______

Correct answer: 18

Explanation: Only a=14a=\frac14.

Question 87

Mathematics · 4 marks · −1

The area of the region enclosed by the parabolas y=x2−5xy=x^2-5x and y=7x−x2y=7x-x^2 is

Correct answer: 72

Explanation: ∫06(12x−2x2)dx=72\int_0^6(12x-2x^2)dx=72.

Question 88

Mathematics · 4 marks · −1

Let a⃗=i^−3j^+7k^\vec a=\hat i-3\hat j+7\hat k, b⃗=2i^−j^+k^\vec b=2\hat i-\hat j+\hat k and c⃗\vec c be a vector such that (a⃗+2b⃗)×c⃗=3(c⃗×a⃗)(\vec a+2\vec b)\times\vec c=3(\vec c\times\vec a). If a⃗⋅c⃗=130\vec a\cdot\vec c=130, then b⃗⋅c⃗\vec b\cdot\vec c is equal to _______

Correct answer: 30

Explanation: (4a⃗+2b⃗)×c⃗=0⃗(4\vec a+2\vec b)\times\vec c=\vec0: c⃗=12(8,−14,30)\vec c=\frac12(8,-14,30).

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