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JEE Main 2019 (12 Apr Shift 2)

2019 · 90 questions · First 10 Solutions Free
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Q1 mcq
Figure shows a $DC$ voltage regulator circuit, with a Zener diode of breakdown voltage $= 6\,V$ . If the unregulated input voltage varies between $10\,V$ to $16\,V,$ then what is the maximum Zener current?
Question 1 image
a.
$1.5\,mA$
b.
$3.5 mA$ Correct Answer
c.
$7.5\,mA$
d.
$2.5\,mA$

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Q2 mcq
A block of mass $5\,kg$ is (i) pushed in case $(A)$ and (ii) pulled in case $(B),$ by a force $F = 20\,N,$ making an angle of $30^{o}$ with the horizontal, as shown in the figures. The coefficient of friction between the block and floor is $\mu = 0.2.$ The difference between the accelerations of the block, in case $(B)$ and case $(A)$ will be: $(g = 10 m\,s^{-2})$
Question 2 image
a.
$3.2\,m\,s^{-2}$
b.
$0\,m\,s^{-2}$
c.
$0.8\,m\,s^{-2}$ Correct Answer
d.
$0.4\,m\,s^{-2}$

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Q3 mcq
A solid sphere, of radius R acquires a terminal velocity $v_{1}$ when falling (due to gravity) through a viscous fluid having a coefficient of viscosity $\eta .$ The sphere is broken into 27 identical solid spheres. If each of these spheres acquires a terminal velocity, $v_{2},$ when falling through the same fluid, the ratio $(\frac{v_{1}}{v_{2}})$ equals:
a.
$\frac{1}{9}$
b.
$27$
c.
$\frac{1}{27}$
d.
$9$ Correct Answer

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Q4 mcq
$1\, kg$ of water, at $20\,^{\circ}C$ is heated in an electric kettle whose heating element has a mean (temperature averaged) resistance of $20 \Omega .$ The rms voltage in the mains is $200\,V$ . Ignoring heat loss from the kettle, time taken for water to evaporate fully is close to [ Specific heat of water $= 4200\,J\, kg^{-1} \,^{\circ}C^{-1}$ Latent heat of water $= 2260\,kJ\,kg^{-1}$ ]
a.
$3\, min$
b.
$16\, min$
c.
$22\, min$ Correct Answer
d.
$10\, min$

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Q5 mcq
An electron, moving along the $x-$ axis with an initial energy of $100\,eV,$ enters a region of magnetic field $\vec{B}=(1.5 \times 10^{-3}\,T)ˆk$ at S (see figure). The field extends between $x= 0$ and $x= 2\,cm.$ The electron is detected at the point $Q$ on a screen placed $8\,cm$ away from the point $S.$ The distance d between $P$ and $Q$ (on the screen) is: (electron’s charge $1.6 \times 10^{-19}\,C$ , mass of electron $= 9.1 \times 10^{-31}\,kg$ )
Question 5 image
a.
$1.22\,cm$
b.
$12.87\,cm$ Correct Answer
c.
$11.65\,cm$
d.
$2.25\,cm$

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Q6 mcq
A particle is moving with speed $v=b\sqrt{x}$ along positive $x-$ axis. Calculate the speed of the particle at time $t=τ$ (assume that the particle is at origin at $t= 0$ )
a.
$b^{2}τ$
b.
$\frac{b^{2}τ}{\sqrt{2}}$
c.
$\frac{b^{2}τ}{2}$ Correct Answer
d.
$\frac{b^{2}τ}{4}$

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Q7 mcq
A diatomic gas with rigid molecules does $10\,J$ of work when expanded at constant pressure. What would be the heat energy absorbed by the gas, in this process?
a.
$40\,J$
b.
$35\,J$ Correct Answer
c.
$25\,J$
d.
$30\,J$

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Q8 mcq
Three particles of masses $50\,g$ , $100\,g$ and $150\,g$ are placed at the vertices of an equilateral triangle of side $1\,m$ (as shown in the figure). The $(x, y)$ coordinates of the centre of mass will be:
Question 8 image
a.
$( \frac{7}{12}\,m, \frac{\sqrt{3}}{4}\,m)$ Correct Answer
b.
$( \frac{7}{12}\,m, \frac{\sqrt{3}}{8}\,m)$
c.
$( \frac{\sqrt{3}}{4}\,m, \frac{5}{12}\,m)$
d.
$( \frac{\sqrt{3}}{8}\,m, \frac{7}{12}\,m)$

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Q9 mcq
A Carnot engine has an efficiency of $\frac{1}{6}.$ When the temperature of the sink is reduced by $62\,$ ℃, its efficiency is doubled. The temperatures of the source and the sink are, respectively,
a.
$124\,$ ℃ $, 62\,$ ℃
b.
$37\,$ ℃ $,\,99\,$ ℃ Correct Answer
c.
$99\,$ ℃ $, \,37\,$ ℃
d.
$62\,$ ℃ $, 124\,$ ℃

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Q10 mcq
A plane electromagnetic wave having a frequency $f = 23.9 GHz$ propagates along the positive $z-$ direction in free space. The peak value of the Electric Field is $60\,V/m.$ Which among the following is the acceptable magnetic field component in the electromagnetic wave?
a.
$\vec{B}= 2 \times 10^{-7} sin(0.5 \times 10^{3}z-1.5 \times 10^{11}t)ˆi$ Correct Answer
b.
$\vec{B}= 2 \times 10^{-7} sin(1.5 \times 10^{3}x+ 0.5 \times 10^{11}t)ˆj$
c.
$\vec{B}= 2 \times 10^{7} sin(0.5 \times 10^{3}z+ 1.5 \times 10^{11}t)ˆi$
d.
$\vec{B}= 60 sin(0.5 \times 10^{3}x+ 1.5 \times 10^{11}t)ˆi$

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Q11 mcq
A tunning fork of frequency $480\,Hz$ is used in an experiment for measuring speed of sound $(v)$ in air by resonance tube method. Resonance is observed to occur at two successive lengths of the air column, $l_{1} = 30 cm$ and $l_{2} = 70 cm.$ Then, $ν$ is equal to:
a.
$384\,m\,s^{-1}$
b.
$332\,m\,s^{-1}$
c.
$338\,m\,s^{-1}$
d.
$379\,m\,s^{-1}$
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Q12 mcq
A spring whose unstrentches length is $l$ has a force constant $k.$ The spring is cut into two pieces of unstretches lengths $l_{1}$ and $l_{2}$ where, $l_{1} =nl_{2}$ and $n$ is an integer. The ratio $k_{1}/k_{2}$ of the corresponding force constants, $k_{1}$ and $k_{2}$ will be:
a.
$\frac{1}{n^{2}}$
b.
$n^{2}$
c.
$n$
d.
$\frac{1}{n}$
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Q13 mcq
Let a total charge $2Q$ be distributed in a sphere of radius $R,$ with the charge density given by $\rho (r) = kr,$ where $r$ is the distance from the centre. Two charges $A$ and $B$ , of $-Q$ each, are placed on diametrically opposite points, at equal distance, a, from the centre. If $A$ and $B$ do not experience any force, then:
a.
$a = \frac{3R}{1}$ $2$
b.
$a = \frac{R}{\sqrt{3}}$
c.
$a = 2\frac{-14}{4}R$
d.
$a = 8\frac{-1}{4} R$
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Q14 mcq
Consider an electron in a hydrogen atom, revolving in its second excited state (having radius $4.65\,$ Å). The de- Broglie wavelength of this electron is:
a.
$12.9\,$ Å
b.
$6.6\,$ Å
c.
$9.7\,$ Å
d.
$3.5\,$ Å
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Q15 mcq
In the given circuit, the charge on $4$ $\mu$ $F$ capacitor will be:
Question 15 image
a.
$9.6$ $\mu$ $C$
b.
$5.4$ $\mu$ $C$
c.
$24$ $\mu$ $C$
d.
$13.4$ $\mu$ $C$
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Q16 mcq
A small speaker delivers $2\,W$ of audio output. At what distance from the speaker will one detect $120\,\,dB$ intensity sound? [Given reference intensity of sound as $10^{-12}\,W/m^{2}$ ]
a.
$40\,cm$
b.
$20\,cm$
c.
$10\,cm$
d.
$30\,cm$
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Q17 mcq
Two sources of sound $S_{1}$ and $S_{2}$ produce sound waves of same frequency $660\,Hz.$ A listener is moving from source $S_{1}$ towards $S_{2}$ with a constant speed $u_{0}\,m/s$ and he hears $10\,beats/s.$ The velocity of sound is $330\,m/s.$ Then, $u_{0}$ equals:
a.
$10.0\,m/s$
b.
$2.5\,m/s$
c.
$5.5\,m/s$
d.
$15.0\,m/s$
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Q18 mcq
Consider the LR circuit shown in the figure. If the switch S is closed at $t = 0$ then the amount of charge that passes through the battery between $t = 0$ and $t = \frac{L}{R}$ is:
a.
$\frac{7.3 EL}{R^{2}}$
b.
$\frac{EL}{7.3R^{2}}$
c.
$\frac{2.7 EL}{R^{2}}$
d.
$\frac{EL}{2.7R^{2}}$
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Q19 mcq
The ratio of the weights of a body on Earth’s surface to that on the surface of a planet is $9 : 4$ The mass of the planet is $\frac{1}{9} th$ of that of the Earth. If $R$ is the radius of the Earth, what is the radius of the planet? (Take the planets to have the same mass density)
a.
$\frac{R}{4}$
b.
$\frac{R}{2}$
c.
$\frac{R}{3}$
d.
$\frac{R}{9}$
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Q20 mcq
Find the magnetic field at point $P$ due to a straight line segment $AB$ of length $6\,cm$ carrying a current of $5\,A.$ (See figure) $(\mu _{0} = 4\pi \times 10^{-7}\, NA^{-2})$
Question 20 image
a.
$1.5 \times 10^{-5}\,T$
b.
$2.0 \times 10^{-5}\,T$
c.
$3.0 \times 10^{-5}\,T$
d.
$2.5 \times 10^{-5}\,T$
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Q21 mcq
The number density of molecules of a gas depends on their distance r from the origin as, $n(r) =n_{0}e^{-\alpha r^{4}}.$ Then the numer of molecules is proportional to:
a.
$n_{0}\alpha ^{-3}$
b.
$\sqrt{n_{0}}\alpha \frac{1}{2}$
c.
$n_{0}\alpha \frac{-3}{4}$
d.
$n_{0}\alpha \frac{1}{4}$
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Q22 mcq
A system of three polarizers $P_{1}, P_{2}, P_{3}$ is set up such that the pass axis of $P_{3}$ is crossed with respect to that of $P_{1}$ . The pass axis of $P_{2}$ is inclined at $60^{o}$ to the pass axis of $P_{3}.$ When a beam of unpolarized light of intensity $I_{o}$ is incident on $P_{1},$ the intensity of light transmitted by the three polarizers is $I$ . The ratio $(I_{o}/I)$ equals (nearly):
a.
$5.33$
b.
$16.00$
c.
$1.80$
d.
$10.67$
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Q23 mcq
A transparent cube of side $d$ , made of a material of refractive index $\mu _{2}$ , is immersed in a liquid of refractive index $\mu _{1}\,(\,\mu _{1} <\mu _{2})$ . A ray is incident on the face $AB$ at an angle $\theta$ (shown in the figure). Total internal reflection takes place at the point $E$ on the face $BC.$ Then, $\theta$ must satisfy
Question 23 image
a.
$\theta < sin^{-1} \sqrt{\,} \frac{\mu ^{2}_{2}}{\mu ^{2}_{1}} -1$
b.
$\theta > sin^{-1} \frac{\mu _{1}}{\mu _{2}}$ $\sqrt{\,}$
c.
$\theta < sin^{-1} \frac{\mu _{1}}{\mu _{2}}$
d.
$\theta > sin^{-1} \frac{\mu ^{2}_{2}}{\mu ^{2}}_{1} -1$
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Q24 mcq
A uniform cylindrical rod of length $L$ and radius r, is made from a material whose Young’s modulus of Elasticity equals $Y.$ When this rod is heated by temperature T and simultaneously subjected to a net longutudinal compressional force F, its length remains unchanged. The coefficient of volume expansion, of the material of the rod, is (nearly) equal to:
a.
$F/(3\pi r^{2}Y T)$
b.
$9F/(\pi r^{2}Y T)$
c.
$6F/(\pi r^{2}Y T)$
d.
$3F/(\pi r^{2}Y T)$
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Q25 mcq
Two particles are projected from the same point with the same speed u such that they have the same range R, but different maximum heights, $h_{1}$ and $h_{2}.$ Which of the following is correct?
a.
$R^{2} = h_{1}h_{2}$
b.
$R^{2} = 4\,h_{1}h_{2}$
c.
$R^{2} = 2\,h_{1}h_{2}$
d.
$R^{2} = 16\,h_{1}h_{2}$
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Q26 mcq
A moving coil galvanometer, having a resistance $G,$ produces full scale deflection when a current $I_{G}$ flows through it. This galvanometer can be converted into (i) an ammeter of range 0 to $I_{o}(I_{0} > I_{g})$ by connecting a shunt resistance $R_{A}$ to it and (ii) into a voltmeter of range 0 to $V(V = GI_{0})$ by connecting a series resistance $R_{V}$ to it. Then,
a.
$R_{A}R_{V} = G^{2}( \frac{I_{0}-I_{g}}{I_{g}})$ and $\frac{R_{A}}{R_{V}} =(\frac{I_{g}}{(I_{0}-I_{g})} )^{2}$
b.
$R_{A}R_{V} = G^{2}$ and $\frac{R_{A}}{R_{V}} = \frac{I_{g}}{(I_{0}-I_{g})}$
c.
$R_{A}R_{V} = G^{2}( \frac{I_{g}}{I_{0}-I_{g}})$ and $\frac{R_{A}}{R_{V}} =(\frac{I_{0}-I_{g}}{I_{g}})^{2}$
d.
$R_{A}R_{V} = G^{2}$ and $\frac{R_{A}}{R_{V}} =(\frac{I_{g}}{I_{0}-I_{g}})^{2}$
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Q27 mcq
In a $CE$ transistor amplifier, the audio signal voltage across the collector resistance of $2\,k\Omega$ is $2\,V$ , if the base resistance is $1\,k\Omega$ and the current amplification of the transistor is $100$ then the input signal voltage is
a.
$10\, mV$
b.
$1\, mV$
c.
$0 .1 \,V$
d.
$1\,V$
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Q28 mcq
A smooth wire of length $2\pi r$ is bent into a circle and kept in a vertical plane. A bead can slide smoothly on the wire. When the circle is rotating with angular speed about the vertical diameter $\omega$ $AB,$ as shown in figure, the bead is at rest with respect to the circular ring at position $P$ as shown. Then the value of $\omega$ $^{2}$ is equal to:
Question 28 image
a.
$2g/r$
b.
$\frac{\sqrt{3}g}{2r}$
c.
$2g/(r\sqrt{3})$
d.
$(g\sqrt{3})/r$
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Q29 mcq
The electron in a hydrogen atom first jumps from the third excited state to the second excited state and subsequently to the first excited state. The ratio of the respective wavelengths $\frac{\lambda _{1}}{\lambda _{2}}$ of the photons emitted in this process is:
a.
$\frac{7}{5}$
b.
$\frac{20}{7}$
c.
$\frac{9}{7}$
d.
$\frac{27}{5}$
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Q30 mcq
Half lives of two radioactive nuclei $A$ and $B$ are 10 minutes and 20 minutes, respectively. If, initially a sample has equal number of nuclei, then after 60 minutes, the ratio of decayed numbers of nuclei A and B will be:
a.
$3 : 8$
b.
$8 : 1$
c.
$1 : 8$
d.
$9 : 8$
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Q31 mcq
The primary pollutant that leads to photochemical smog is:
a.
nitrogen oxides
b.
ozone
c.
acrolein
d.
Sulphur dioxide
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Q32 mcq
In the following skew conformation of ethane, $H' -C -C -H''$ dihedral angle is:
Question 32 image
a.
$58^{o}$
b.
$120^{o}$
c.
$149^{o}$
d.
$151^{o}$
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Q33 mcq
Which of the given statements is incorrect about glycogen?
a.
It is present in animal cells.
b.
It is a straight chain polymer similar to amylose.
c.
It is present in some yeast and fungi
d.
Only $\alpha$ $-$ linkages are present in the molecule.
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Q34 mcq
Consider the following reactions: ‘A’ is:
Question 34 image
a.
$CH_{2} = CH_{2}$
b.
$CH \equiv CH$
c.
$CH_{3}-C \equiv C -CH_{3}$
d.
$CH_{3}-C \equiv CH$
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Q35 mcq
What will be the major product when m-cresol is reacted with propargyl bromide $(HC \equiv C -CH_{2}Br)$ in presence of $K_{2}CO_{3}$ in acetone?
Question 35 image
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Q36 mcq
The $C -C$ bond length is maximum in:
a.
$C_{70}$
b.
$C_{60}$
c.
graphite
d.
diamond
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Q37 mcq
The correct name of the following polymer is:
Question 37 image
a.
Polyisobutylene
b.
Polytert-butylene
c.
Polyisobutane
d.
Polyisoprene
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Q38 mcq
The molar solubility of $Cd(OH)_{2}$ is $1.84 \times 10^{-5}M$ in water. The expectes solunility of $Cd(OH)_{2}$ in a buffer solution of $pH = 12$ is:
a.
$2.49 \times 10^{-10}M$
b.
$\frac{2.49}{1.84} \times 10^{-9}M$
c.
$1.84 \times 10^{-9}M$
d.
$6.23 \times 10^{-11}M$
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Q39 mcq
The ratio of number of atoms present in a simple cubic, body centered cubic and face centered cubic structure are, respectively :
a.
$4 : 2 : 1$
b.
$1 : 2 : 4$
c.
$4 : 2 : 3$
d.
$8 : 1 : 6$
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Q40 mcq
Benzene diazonium chloride on reaction with aniline in the presence of dilute hydrochloric acid gives:
Question 40 image
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Q41 mcq
The decreasing order of electrical conductivity of the following aqueous solutions is: $(A) 0.1\,M$ Formic acid, $(B) 0.1\,M$ Acetic acid, $(C) 0.1\,M$ Benzoic acid.
a.
$(A) > \,(B) > \,(C)$
b.
$(A) > \,(C) > \,(B)$
c.
$(C) > \,(B) > \,(A)$
d.
$(C) > \,(A) > \,(B)$
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Q42 mcq
In which one of the following equilibria, $K_{p} \neq K_{c}?$
a.
$2HI(g) \rightleftharpoons H_{2}(g) + I_{2}(g)$
b.
$2C(s) + O_{2}(g) \rightleftharpoons 2CO(g)$
c.
$2NO(g) \rightleftharpoons N_{2}(g) + O_{2}(g)$
d.
$NO_{2}(g) + SO_{2}(g) \rightleftharpoons NO(g) + SO_{3}(g)$
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Q43 mcq
The pair that has similar atomic radii is:
a.
$Mo$ and $W$
b.
$Sc$ and $Ni$
c.
$Mn$ and $Re$
d.
$Ti$ and $Hf$
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Q44 mcq
$NO_{2}$ required for a reaction is produced by the decomposition of $N_{2}O_{5}$ in $CCl_{4}$ as per the equation, $2N_{2}O_{5}(g) \rightarrow 4NO\rightarrow_{2}(g) + O_{2}(g).$ The initial concentration of $N_{2}O_{5}$ is $3.00\,mol\,L^{-1}$ and it is $2.75\,mol\,L^{-1}$ after 30 minutes. The rate of formation of $NO_{2}$ is:
a.
$1.667 \times 10^{-2} mol L^{-1} min^{-1}$
b.
$8.333 \times 10^{-3} mol L^{-1}min^{-1}$
c.
$4.167 \times 10^{-3} mol L^{-1}min^{-1}$
d.
$2.083 \times 10^{-3} mol L^{-1} min^{-1}$
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Q45 mcq
The IUPAC name for the following compound is:
Question 45 image
a.
$3-$ methyl $-4-1-$ ( methylprop $-2-$ ynyl) $-1-$ heptene
b.
$3, \,5-$ dimethyl $-4-$ propylhept $-6-$ en $-1-$ yne
c.
$3, \,5-$ dimethyl $-4-$ propyl hept $-1-$ en $-6-$ yne
d.
$3-$ methyl $-4-3-$ ( methylprop $-1-$ enhyl) $-1-$ heptyne
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Q46 mcq
Heating of 2-chloro-1-phenylbutane with $EtOK/EtOH$ gives $X$ as the major product. Reaction $X$ with $Hg(OAc)_{2}/H_{2}O$ followed by $NaBH_{4}$ gives $Y$ as the major product. $Y$ is:
Question 46 image
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Q47 mcq
An ‘Assertion’ and a ‘Reason’ is given below. Choose the correct answer from the following options: Assertion $(A)$ : Vinyl halides do not undergo nucleophilic substitution easily. Reason $(R)$ : Even though the intermediate carbocation is stabilized by loosely held $\pi$ $-$ electrons, the cleavage is difficult because of the strong bonding.
a.
Both $(A)$ and $(R)$ are correct statements but $(R)$ is not the correct explanation of $(A).$
b.
Both $(A)$ and $(R)$ are wrong statements.
c.
Both $(A)$ and $(R)$ are wrong statements and $(R)$ is the correct explanation of $(A).$
d.
$(A)$ is a correct statement but $(R)$ is a wrong statement.
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Q48 mcq
$25\,g$ of an unknown hydrocarbon upon burnig produces $88\,g$ of $CO_{2}$ and $9g$ of $H_{2}O.$ This unknown hydrocarbon contains:
a.
$24\,g$ of carbon and $1\,g$ of hydrogen
b.
$18\,g$ of carbon annd $7\,g$ of hydrogen
c.
$22\,g$ of carbon and $3\,g$ of hydrogen
d.
$20\,g$ carbon and $5\,g$ of hydrogen
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Q49 mcq
A solution is prepared by dissolving 0.6 g of urea (molar mass $= 60\,g\,mol^{-1}$ ) and $1.8\,g$ of glucose (molar mass $= 180\,g\,mol^{-1}$ ) in 100 mL of water at $27^{o}C.$ The osmotic pressure of the solution is: ( $R = 0.08206\,Latm K^{-1}\,mol^{-1}$ )
a.
$8.2$ atm
b.
$2.46$ atm
c.
$4.92$ atm
d.
$1.64$ atm
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Q50 mcq
Among the following, the energy of $2s$ orbital is lowest in:
a.
$K$
b.
$H$
c.
$Na$
d.
$Li$
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Q51 mcq
The coordination numbers of $Co$ and $Al$ in $[Co(Cl)(en)_{2}]Cl$ and $K_{3}[Al(C_{2}O_{4})_{3}],$ respectively are: (en $=$ ethane-1, 2-diamine)
a.
3 and 3
b.
5 and 3
c.
5 and 6
d.
6 and 6
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Q52 mcq
Which one of the following is likely to give a precipitate with $AgNO_{3}$ solution?
a.
$CH_{2} = CH -Cl$
b.
$(CH_{3})_{3}CCl$
c.
$CCl_{4}$
d.
$CHCl_{3}$
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Q53 mcq
In comparison to boron, berylium has:
a.
greater nuclear charge and lesser first ionisation enthalpy
b.
lesser nuclear charge and greater first ionisation enthalpy
c.
lesser nuclear charge and lesser first ionisation enthalpy.
d.
greater nuclear charge and greater first ionisation enthalpy.
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Q54 mcq
The correct statement is:
a.
Pig iron is obtained from cast iron.
b.
The Hall-Heroult process is used for the production of aluminium and iron.
c.
leaching of bauxite using concentrated $NaOH$ solution gives sodium aluminate and sodium silicate.
d.
the blistered appearance of copper during the metallurgical process is due to the evolution of $CO_{2}.$
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Q55 mcq
The incorrect match in the following is:
a.
$\Delta G^{0} < 0, K > 1$
b.
$\Delta G^{0} > 0, K < 1$
c.
$\Delta G^{0} = 0, K = 1$
d.
$\Delta G^{0} < 0, K < 1$
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Q56 mcq
The temporary hardness of a water sample is due to compound $X.$ Boiling this sample converts $X$ to compound $Y. X$ and $Y,$ respectively, are:
a.
$Mg(HCO_{3})_{2}$ and $MgCO_{3}$
b.
$Ca(HCO_{3})_{2}$ and $Ca(OH)_{2}$
c.
$Mg(HCO_{3})_{2}$ and $Mg(OH)_{2}$
d.
$Ca(HCO_{3})_{2}$ and $CaO$
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Q57 mcq
The compound used in the treatment of lead poisoning is:
a.
Desferrioxime B
b.
EDTA
c.
Cis-platin
d.
$D-$ penicillamine
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Q58 mcq
The incorrect statement is:
a.
$LiNO_{3}$ decomposes on heating to give $LiNO_{2}$ and $O_{2}.$
b.
$LiCl$ crystallises from aqueous solution as $LiCl -2H_{2}O$ .
c.
Lithium is the strongest reducing agent among the alkali metals.
d.
Lithium is least reactive with water among the alkali metals.
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Q59 mcq
Among the following, the incorrect statement about colloids is:
a.
They are larger than small molecules and have high molar mass.
b.
They can scatter lighht.
c.
The osmotic pressure of a collodial solution is of higher order than the true solution at the same concentration.
d.
The range of diameters of colloidal particles is between $1$ and $1000\,nm.$
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Q60 mcq
Thermal decomposition of a Mn compound $(X)$ at $513\,K$ results in compound $Y, MnO_{2}$ and a gaseous product. $MnO_{2}$ reacts with $NaCl$ and concentrated $H_{2}SO_{4}$ to give a pungent gas $Z$ . $X, \,Y$ and $Z,$ respectively, are:
a.
$K_{3}MnO_{4}, K_{3}MnO_{4}$ and $Cl_{2}$
b.
$K_{2}MnO_{4}, KMnO_{4}$ and $Cl_{2}$
c.
$K_{2}MnO_{4}, KMnO_{4}$ and $SO_{2}$
d.
$KMnO_{4}, K_{2}MnO_{4}$ and $Cl_{2}$
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Q61 mcq
The angle of the top of a vertical tower standing on a horizontal plane is observed to be $45^{\circ}$ from a point A on the plane. Let $B$ be the point $30\,m$ vertically above the point A. If the angle of elevation of the top of the tower from $B$ be $30^{\circ}$ , then the distance (in m) of the foot of the tower from the point $A$ is:
a.
$15(3 + \sqrt{3})$
b.
$15(1 + \sqrt{3})$
c.
$15(5 - \sqrt{3})$
d.
$15(3 - \sqrt{3})$
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Q62 mcq
$_{x}lim_{\rightarrow 0\rightarrow } \frac{x+2sinx}{\sqrt{x^{2}+2\,sin\,x+1}\,-\,\sqrt{sin^{2}x-x+1}}$ is
a.
$3$
b.
$1$
c.
$2$
d.
$6$
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Q63 mcq
$1 + cos^{2}\theta sin^{2}\theta 4 cos6\theta$ A value of $\theta \in (0, \frac{\pi}{3}),$ for which $cos^{2}\theta 1 + sin^{2}\theta 4 cos6\theta = 0,$ is $cos^{2}\theta sin^{2}\theta 1 + 4 cos6\theta$
a.
$\frac{\pi}{9}$
b.
$\frac{7\pi}{24}$
c.
$\frac{7\pi}{36}$
d.
$\frac{\pi}{18}$
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Q64 mcq
Let $z\in C$ with $Im(z) = 10$ and it satisfies $\frac{2z-n}{2z+n} = 2i-1$ for some natural number $n.$ Then
a.
$n= 20$ and $Re(z) = 10$
b.
$n= 40\,$ and $\,Re(z) = 10$
c.
$n= 20$ and $Re(z) = -10$
d.
$n= 40$ and $Re(z) = -10$
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Q65 mcq
Let $S$ be the set of all $\alpha \in R$ such that the equation, $cos2x+\alpha sinx= 2\alpha -7$ has a solution. Then $S$ is equal to:
a.
$[3, \,7]$
b.
$[2, \,6]$
c.
$[1, \,4]$
d.
R
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Q66 mcq
$\alpha +1$ A value of $\alpha$ such that $\int \frac{dx}{(x+\alpha )(x+\alpha +1)} = log_{e}( \frac{9}{8})$ is $\alpha$
a.
$-\frac{1}{2}$
b.
$\frac{1}{2}$
c.
$-2$
d.
$2$
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Q67 mcq
The term independent of $x$ in the expansion of $(\frac{1}{60} - \frac{x^{8}}{81}).(2x^{2}- \frac{3}{x^{2}})^{6}$ is equal to
a.
$-72$
b.
$36$
c.
$-108$
d.
$-36$
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Q68 mcq
A triangle has a vertex at $(1, \,2)$ and the mid points of the two sides through it are $(-1, \,1)$ and $(2, \,3)$ . Then the centroid of this triangle is:
a.
$( \frac{1}{3}, 1)$
b.
$(1, \,\frac{7}{3} )$
c.
$( \frac{1}{3}, \,2)$
d.
$(\frac{1}{3}, \,\frac{5}{3})$
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Q69 mcq
The general solution of the differential equation $(y^{2} - x^{3})dx- xydy= 0, \,(x\neq 0)$ is (where c is a constant of integration)
a.
$y^{2} + 2x^{2} +cx^{3} = 0$
b.
$y^{2} -2x^{2} +cx^{3} = 0$
c.
$y^{2} -2x^{3} +cx^{2} = 0$
d.
$y^{2} + 2x^{3} +cx^{2} = 0$
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Q70 mcq
A person throws two fair dice. He wins Rs. $15$ for throwing a doublet (same numbers on the two dice), wins Rs $12$ when the throw results in the sum of $9$ , and loses Rs. $6$ for any other outcome on the throw. Then the expected gain/loss (in Rs.) of the person is:
a.
$\frac{1}{2}$ loss
b.
$\frac{1}{2}$ gain
c.
2 gain
d.
$\frac{1}{4}$ loss
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Q71 mcq
If the area (in sq. units) bounded by the parabola $y^{2} = 4\lambda x$ and the line $y=\lambda x, \lambda > 0,$ is $\frac{1}{9}$ , then $\lambda$ is equal to
a.
$4\sqrt{3}$
b.
$2\sqrt{6}$
c.
$48$
d.
$24$
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Q72 mcq
If $[x]$ denotes the greatest integer $\leq x,$ then the system of linear equations $[sin\theta ]x+ [-cos\theta ]y= 0$ , $[cot\theta ]x+y= 0$
a.
has a unique solution if $\theta \in (\frac{\pi}{2}, \frac{2\pi}{3})\cup (\pi , \frac{7\pi}{6})$
b.
have infinitely many solution if $\theta \in (\frac{\pi}{2} , \frac{2\pi}{3})\cup (\pi , \frac{7\pi}{6})$
c.
has a unique if $\theta \in (\frac{\pi}{2}, \frac{2\pi}{3} )$ and have infinitely many solutions if $\theta \in (\pi , \frac{7\pi}{6} )$
d.
have infinitely many solutions if $\theta \in (\frac{\pi}{2}, \frac{2\pi}{3} )$ and has a unique solution if $\theta \in (\pi , \frac{7\pi}{6})$
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Q73 mcq
A plane which bisects the angle between the two given planes $2x- y+ 2z-4 = 0$ and $x+ 2y+ 2z-2 = 0$ , passes through the point
a.
$(2, \,4, \,1)$
b.
$(1, -4, \,1)$
c.
$(1, \,4, -1)$
d.
$(2, -4, \,1)$
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Q74 mcq
If $\alpha ,\beta$ and $\gamma$ are three consecutive terms of a non-constant G.P. Such that the equations $\alpha x^{2} + 2\beta x+\gamma = 0$ and $x^{2} +x-1 = 0$ have a common root, then $\alpha (\beta +\gamma )$ is equal to:
a.
$\beta \gamma$
b.
$\alpha \beta$
c.
$\alpha \gamma$
d.
$0$
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Q75 mcq
A straight line $L$ at a distance of $4$ units from the origin makes positive intercepts on the coordinate axes and the perpendicular from the origin to this line makes an angle of $60^{\circ}$ with the line $x+y= 0.$ Then an equation of the line $L$ is: Note: In actual JEE Main paper, two options were correct for this question. Hence, we have changed one option.
a.
$(\sqrt{3}+ 1)x+(\sqrt{3}-1)y= 8\sqrt{2}$
b.
$x+ \sqrt{3}y= 8$
c.
$\sqrt{3}x+y= 8$
d.
$(\sqrt{3}-1)x+ \sqrt{3}y= 8\sqrt{2}$
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Q76 mcq
An ellipse, with foci at $(0,2)$ and $(0, -2)\,$ and minor axis of length $4$ , passes through which of the following points?
a.
$(1, \,2\sqrt{2})$
b.
$(2, \,\sqrt{2})$
c.
$(\sqrt{2}, \,2)$
d.
$(2, \,2\sqrt{2})$
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Q77 mcq
Let $\alpha \in R$ and the three vectors $\vec{a}=\alpha ˆi+ ˆj+ 3ˆk, \vec{b}= 2ˆi+ ˆj- \alpha ˆk$ and $\vec{c}=\alpha ˆi-2ˆj+ 3ˆk.$ Then the set S = { $\alpha : \vec{a}, \vec{b}$ and $\vec{c}$ are coplanar}
a.
is singleton
b.
contains exactly two positive numbers
c.
is empty
d.
contains exactly two numbers only one of which is positive
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Q78 mcq
If $a_{1},a_{2},a_{3}, . . . .$ are in A.P. such that $a_{1}+a_{7}+a_{16} = 40,$ then the sum of the first $15$ terms of this A.P is:
a.
$280$
b.
$120$
c.
$150$
d.
$200$
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Q79 mcq
The equation of a common tangent to the curves, $y^{2} = 16x$ and $xy= -4,$ is:
a.
$x-2y+ 16 = 0$
b.
$x- y+ 4 = 0$
c.
$2x- y+ 2 = 0$
d.
$x+y+ 4 = 0$
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Q80 mcq
If $^{20}C_{1}+(2^{2})^{20}C_{2}+(3^{2})^{20}C_{3}+. . . . . +(20^{2})^{20}C_{20} =A(2^{\beta }),$ then the ordered pair $(A,\beta )$ is equal to
a.
$(380, \,19)$
b.
$(420, \,18)$
c.
$(420, \,19)$
d.
$(380, \,18)$
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Q81 mcq
Let $A, \,B$ and $C$ be sets such that $\phi \neq A\cap B⊆ C.$ Then which of the following statements is not true?
a.
$B\cap C \neq \phi$
b.
$(C\cup A) \cap (C\cup B) =C$
c.
If $(A- B) ⊆ C,$ then $A⊆ C$
d.
If $(A- C) ⊆ B,$ then $A⊆ B$
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Q82 mcq
For an initial screening of an admission test, a candidate is given fifty problems to solve. If the probability that the candidate can solve any problem is $\frac{4}{5} ,$ then the probability that he is unable to solve less than two problems is
a.
$\frac{201}{5}(\frac{1}{5})^{49}$
b.
$\frac{164}{25} ( \frac{1}{5})^{48}$
c.
$\frac{316}{25}(\frac{4}{5})^{48}$
d.
$\frac{54}{5}(\frac{4}{5})^{49}$
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Q83 mcq
The derivative of $tan^{-1}(\frac{sinx-cosx}{sinx+cosx})$ with respect to $\frac{x}{2} ,$ where $x\in (0, \frac{\pi}{2} )$ , is
a.
$2$
b.
$\frac{1}{2}$
c.
$\frac{2}{3}$
d.
$1$
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Q84 mcq
The Boolean expression $\sim (p\Rightarrow (\sim q))$ is equivalent to
a.
$(\sim p) \Rightarrow q$
b.
$q\Rightarrow \sim p$
c.
$p\vee q$
d.
$p\wedge q$
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Q85 mcq
Let $f(x) = 5 -|x-2|$ and $g(x) = |x+ 1|,x\, \in \,R.$ If $f(x)$ attains maximum value at $\alpha$ and $g(x)$ attains minimum value at $\beta ,$ then $_{x\rightarrow -\rightarrow }lim_{\alpha \beta } \frac{(x-1)(x^{2}-5x+6)}{x^{2}-6x+8}$ is equal to
a.
$\frac{3}{2}$
b.
$\frac{1}{2}$
c.
$-\frac{3}{2}$
d.
$-\frac{1}{2}$
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Q86 mcq
The tangents to the curve $y= (x-2)^{2} -1$ at its points of intersection with the line $x- y= 3,$ intersect at the point:
a.
$( \frac{5}{2}, 1)$
b.
$(\frac{5}{2}, -1)$
c.
$(-\frac{5}{2} , -1)$
d.
$(-\frac{5}{2}, 1)$
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Q87 mcq
The length of the perpendicular drawn from the point $(2, \,1, \,4)$ to the plane containing the lines $\vec{r}=(ˆi+ ˆj)+\lambda (ˆi+ 2ˆj- ˆk)$ and $\vec{r}=(ˆi+ ˆj)+\mu (-ˆi+ ˆj-2ˆk)$ is
a.
$\frac{1}{3}$
b.
$3$
c.
$\sqrt{3}$
d.
$\frac{1}{\sqrt{3}}$
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Q88 mcq
$| |$ Let $\alpha \in (0, \frac{\pi}{2})$ , be constant.If the integral $\int \frac{tanx+tan\alpha}{tanx-tan\alpha}dx=A(x)cos2\alpha +B(x)sin2\alpha +C$ , where C is a constant of integration, then the functions $A(x)$ and $B(x)$ are respectively
a.
$x- \alpha$ and $log_{e}|sin(x- \alpha )|$
b.
$x+\alpha$ and $log_{e}|cos(x- \alpha )|\,$
c.
$x+\alpha$ and $log_{e}|sin(x+\alpha )|$
d.
$x- \alpha$ and $log_{e}|cos(x- \alpha )|$
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Q89 mcq
A group of students comprises of $5$ boys and n girls. If the number of ways, in which a team of $3$ students can randomly be selected from this group such that there is at least one boy and at least one girl in each team, is $1750,$ then n is equal to
a.
$24$
b.
$27$
c.
$25$
d.
$28$
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Q90 mcq
A circle touching the $x-$ axis at $(3, \,0)$ and making an intercept of length $8$ on the $y-$ axis passes through the point:
a.
$(3, \,10)\,$
b.
$(2, \,3)\,$
c.
$(3, \,5)\,\,$
d.
$(1, \,5)$
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