JEE Main 2020 (Online) 9th January Morning Slot
Paper was held on Thu, Jan 9, 2020 3:30 AM
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Chemistry

1
Identify (A) in the following reaction sequence : JEE Main 2020 (Online) 9th January Morning Slot Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 167 English
2
If enthalpy of atomisation for Br2(1) is x kJ/mol and bond enthalpy for Br2 is y kJ/mol, the relation between them :
3
If the magnetic moment of a dioxygen species is 1.73 B.M, it may be :
4
[Pd(F)(Cl)(Br)(I)]2– has n number of geometrical isomers. Then, the spin-only magnetic moment and crystal field stabilisation energy [CFSE] of [Fe(CN)6]n–6, respectively, are:
[Note : Ignore the pairing energy]
5
The Ksp for the following dissociation is 1.6 × 10–5

$$PbC{l_{2(s)}} \leftrightharpoons Pb_{(aq)}^{2 + } + 2Cl_{(aq)}^ - $$

Which of the following choices is correct for a mixture of 300 mL 0.134 M Pb(NO3)2 and 100 mL 0.4 M NaCl ?
6
The correct order of heat of combustion for following alkadienes is :
JEE Main 2020 (Online) 9th January Morning Slot Chemistry - Hydrocarbons Question 97 English 1 JEE Main 2020 (Online) 9th January Morning Slot Chemistry - Hydrocarbons Question 97 English 2 JEE Main 2020 (Online) 9th January Morning Slot Chemistry - Hydrocarbons Question 97 English 3
7
For the following reactions
$$A\buildrel {700K} \over \longrightarrow {\mathop{\rm Product}\nolimits} $$
$$A\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{catalyst}^{500K}} {\mathop{\rm Product}\nolimits} $$
it was found that Ea is decreased by 30 kJ/mol in the presence of catalyst.
If the rate remains unchanged, the activation energy for catalysed reaction is (Assume pre exponential factor is same):
8
The increasing order of basicity for the following intermediates is (from weak to strong)
JEE Main 2020 (Online) 9th January Morning Slot Chemistry - Basics of Organic Chemistry Question 172 English 1 JEE Main 2020 (Online) 9th January Morning Slot Chemistry - Basics of Organic Chemistry Question 172 English 2 JEE Main 2020 (Online) 9th January Morning Slot Chemistry - Basics of Organic Chemistry Question 172 English 3 JEE Main 2020 (Online) 9th January Morning Slot Chemistry - Basics of Organic Chemistry Question 172 English 4 JEE Main 2020 (Online) 9th January Morning Slot Chemistry - Basics of Organic Chemistry Question 172 English 5
9
The electronic configurations of bivalent europium and trivalent cerium are
(atomic number : Xe = 54, Ce = 58, Eu = 63)
10
How much amount of NaCl should be added to 600 g of water ($$\rho $$ = 1.00 g/mL) to decrease the freezing point of water to – 0.2 °C ? ______.
(The freezing point depression constant for water = 2K kg mol–1)
11
The mass percentage of nitrogen in histamine is _____.
12
108 g of silver (molar mass 108 g mol–1) is deposited at cathode from AgNO3(aq) solution by a certain quantity of electricity. The volume (in L) of oxygen gas produced at 273 K and 1 bar pressure from water by the same quantity of electricity is _______.
13
The molarity of HNO3 in a sample which has density 1.4 g/mL and mass percentage of 63% is _____.
(Molecular Weight of HNO3 = 63)
14
The hardness of a water sample containing 10–3 M MgSO4 expressed as CaCO3 equivalents (in ppm) is ______.
(molar mass of MgSO4 is 120.37 g/mol)
15
The de Broglie wavelength of an electron in the 4th Bohr orbit is :
16
The major product (Y) in the following reactions is : JEE Main 2020 (Online) 9th January Morning Slot Chemistry - Hydrocarbons Question 96 English
17
Complex X of composition Cr(H2O)6Cln has a spin only magnetic moment of 3.83 BM. It reacts with AgNO3 and shows geometrical isomerism. The IUPAC nomenclature of X is :
18
The compound that cannot act both as oxidising and reducing agent is :
19
Which of these will produce the highest yield in Friedel Crafts reaction?
20
The major product Z obtained in the following reaction scheme is : JEE Main 2020 (Online) 9th January Morning Slot Chemistry - Compounds Containing Nitrogen Question 166 English
21
The acidic, basic and amphoteric oxides, respectively, are :
22
B has a smaller first ionization enthalpy than Be. Consider the following statements :

(I) It is easier to remove 2p electron than 2s electron

(II) 2p electron of B is more shielded from the nucleus by the inner core of electrons than the 2s electrons of Be.

(III) 2s electron has more penetration power than 2p electron.

(IV) atomic radius of B is more than Be (Atomic number B = 5, Be = 4)

The correct statements are :

Mathematics

1
If ƒ'(x) = tan–1(secx + tanx), $$ - {\pi \over 2} < x < {\pi \over 2}$$,
and ƒ(0) = 0, then ƒ(1) is equal to :
2
The value of
$$\int\limits_0^{2\pi } {{{x{{\sin }^8}x} \over {{{\sin }^8}x + {{\cos }^8}x}}} dx$$ is equal to :
3
In a box, there are 20 cards, out of which 10 are lebelled as A and the remaining 10 are labelled as B. Cards are drawn at random, one after the other and with replacement, till a second A-card is obtained. The probability that the second A-card appears before the third B-card is :
4
Let z be complex number such that
$$\left| {{{z - i} \over {z + 2i}}} \right| = 1$$ and |z| = $${5 \over 2}$$.
Then the value of |z + 3i| is :
5
A spherical iron ball of 10 cm radius is coated with a layer of ice of uniform thickness the melts at a rate of 50 cm3/min. When the thickness of ice is 5 cm, then the rate (in cm/min.) at which of the thickness of ice decreases, is :
6
If the number of five digit numbers with distinct digits and 2 at the 10th place is 336 k, then k is equal to :
7
Let ƒ be any function continuous on [a, b] and twice differentiable on (a, b). If for all x $$ \in $$ (a, b), ƒ'(x) > 0 and ƒ''(x) < 0, then for any c $$ \in $$ (a, b), $${{f(c) - f(a)} \over {f(b) - f(c)}}$$ is greater than :
8
The projection of the line segment joining the points (1, –1, 3) and (2, –4, 11) on the line joining the points (–1, 2, 3) and (3, –2, 10) is ____________.
9
If for x $$ \ge $$ 0, y = y(x) is the solution of the differential equation
(x + 1)dy = ((x + 1)2 + y – 3)dx, y(2) = 0, then y(3) is equal to _______.
10
The coefficient of x4 is the expansion of (1 + x + x2)10 is _____.
11
If for some $$\alpha $$ and $$\beta $$ in R, the intersection of the following three places
x + 4y – 2z = 1
x + 7y – 5z = b
x + 5y + $$\alpha $$z = 5
is a line in R3, then $$\alpha $$ + $$\beta $$ is equal to :
12
The number of distinct solutions of the equation
$${\log _{{1 \over 2}}}\left| {\sin x} \right| = 2 - {\log _{{1 \over 2}}}\left| {\cos x} \right|$$ in the interval [0, 2$$\pi $$], is ____.
13
The integral $$\int {{{dx} \over {{{(x + 4)}^{{8 \over 7}}}{{(x - 3)}^{{6 \over 7}}}}}} $$ is equal to :
(where C is a constant of integration)
14
If $$f(x) = \left\{ {\matrix{ {{{\sin (a + 2)x + \sin x} \over x};} & {x < 0} \cr {b\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,;} & {x = 0} \cr {{{{{\left( {x + 3{x^2}} \right)}^{{1 \over 3}}} - {x^{ {1 \over 3}}}} \over {{x^{{4 \over 3}}}}};} & {x > 0} \cr } } \right.$$
is continuous at x = 0, then a + 2b is equal to :
15
Let C be the centroid of the triangle with vertices (3, –1), (1, 3) and (2, 4). Let P be the point of intersection of the lines x + 3y – 1 = 0 and 3x – y + 1 = 0. Then the line passing through the points C and P also passes through the point :
16
The value of
$${\cos ^3}\left( {{\pi \over 8}} \right)$$$${\cos}\left( {{3\pi \over 8}} \right)$$+$${\sin ^3}\left( {{\pi \over 8}} \right)$$$${\sin}\left( {{3\pi \over 8}} \right)$$
is :
17
If for all real triplets (a, b, c), ƒ(x) = a + bx + cx2; then $$\int\limits_0^1 {f(x)dx} $$ is equal to :
18
If e1 and e2 are the eccentricities of the ellipse, $${{{x^2}} \over {18}} + {{{y^2}} \over 4} = 1$$ and the hyperbola, $${{{x^2}} \over 9} - {{{y^2}} \over 4} = 1$$ respectively and (e1, e2) is a point on the ellipse, 15x2 + 3y2 = k, then k is equal to :
19
Let the observations xi (1 $$ \le $$ i $$ \le $$ 10) satisfy the
equations, $$\sum\limits_{i = 1}^{10} {\left( {{x_1} - 5} \right)} $$ = 10 and $$\sum\limits_{i = 1}^{10} {{{\left( {{x_1} - 5} \right)}^2}} $$ = 40.
If $$\mu $$ and $$\lambda $$ are the mean and the variance of the
observations, x1 – 3, x2 – 3, ...., x10 – 3, then
the ordered pair ($$\mu $$, $$\lambda $$) is equal to :
20
The number of real roots of the equation,
e4x + e3x – 4e2x + ex + 1 = 0 is :

Physics

1
In a fluorescent lamp choke (a small transformer) 100 V of reverse voltage is produced when the choke current changes uniformly from 0.25 A to 0 in a duration of 0.025 ms. The self-inductance of the choke (in mH) is estimated to be ________.
2
Both the diodes used in the circuit shown are assumed to be ideal and have negligible resistance when these are forward biased. Built in potential in each diode is 0.7 V. For the input voltages shown in the figure, the voltage (in Volts) at point A is __________. JEE Main 2020 (Online) 9th January Morning Slot Physics - Semiconductor Question 143 English
3
A body of mass m = 10 kg is attached to one end of a wire of length 0.3 m. The maximum angular speed (in rad s–1) with which it can be rotated about its other end in space station is :
(Breaking stress of wire = 4.8 × 107 Nm–2 and
area of cross-section of the wire = 10–2 cm2) is:
4
The distance x covered by a particle in one dimensional motion varies with time t as
x2 = at2 + 2bt + c. If the acceleration of the particle depends on x as x–n, where n is an integer, the value of n is __________
5
One end of a straight uniform 1m long bar is pivoted on horizontal table. It is released from rest when it makes an angle 30º from the horizontal (see figure). Its angular speed when it hits the table is given as $$\sqrt n $$ s-1, where n is an integer. The value of n is _________. JEE Main 2020 (Online) 9th January Morning Slot Physics - Rotational Motion Question 137 English
6
Water flows in a horizontal tube (see figure).
The pressure of water changes by 700 Nm–2
between A and B where the area of cross section
are 40 cm2 and 20 cm2, respectively. Find the
rate of flow of water through the tube.
(density of water = 1000 kgm–3) JEE Main 2020 (Online) 9th January Morning Slot Physics - Properties of Matter Question 199 English
7
JEE Main 2020 (Online) 9th January Morning Slot Physics - Rotational Motion Question 138 English Three solid spheres each of mass m and diameter d are stuck together such that the lines connecting the centres form an equilateral triangle of side of length d. The ratio I0/IA of moment of inertia I0 of the system about an axis passing the centroid and about center of any of the spheres IA and perpendicular to the plane of the triangle is :
8
An electric dipole of moment
$$\overrightarrow p = \left( { - \widehat i - 3\widehat j + 2\widehat k} \right) \times {10^{ - 29}} $$ C.m is
at the origin (0, 0, 0). The electric field due to this dipole at
$$\overrightarrow r = + \widehat i + 3\widehat j + 5\widehat k$$ (note that $$\overrightarrow r .\overrightarrow p = 0$$ ) is parallel to :
9
Three harmonic waves having equal frequency $$\nu $$ and same intensity $${I_0}$$, have phase angles 0, $${\pi \over 4}$$ and $$ - {\pi \over 4}$$ respectively. When they are superimposed the intensity of the resultant wave is close to :
10
A charged particle of mass 'm' and charge 'q' moving under the influence of uniform electric field $$E\overrightarrow i $$ and a uniform magnetic field $$B\overrightarrow k $$ follows a trajectory from point P to Q as shown in figure. The velocities at P and Q are respectively, $$v\overrightarrow i $$ and $$ - 2v\overrightarrow j $$ . Then which of the following statements (A, B, C, D) are the correct ?
(Trajectory shown is schematic and not to scale) : JEE Main 2020 (Online) 9th January Morning Slot Physics - Magnetic Effect of Current Question 140 English
(A) E = $${3 \over 4}\left( {{{m{v^2}} \over {qa}}} \right)$$

(B) Rate of work done by the electric field at P is $${3 \over 4}\left( {{{m{v^3}} \over a}} \right)$$

(C) Rate of work done by both the fields at Q is zero

(D) The difference between the magnitude of angular momentum of the particle at P and Q is 2mav.
11
Which of the following is an equivalent cyclic process corresponding to the thermodynamic cyclic given in the figure ? where, 1 $$ \to $$ 2 is adiabatic.
(Graphs are schematic and are not to scale) JEE Main 2020 (Online) 9th January Morning Slot Physics - Heat and Thermodynamics Question 284 English
12
In the given circuit diagram, a wire is joining points B and D. The current in this wire is : JEE Main 2020 (Online) 9th January Morning Slot Physics - Current Electricity Question 223 English
13
Two particles of equal mass m have respective
initial velocities $$u\widehat i$$ and $$u\left( {{{\widehat i + \widehat j} \over 2}} \right)$$.
They collide completely inelastically. The energy lost in the process is :
14
If the screw on a screw-gauge is given six rotations, it moves by 3 mm on the main scale. If there are 50 divisions on the circular scale the least count of the screw gauge is :
15
Consider two ideal diatomic gases A and B at some temperature T. Molecules of the gas A are rigid, and have a mass m. Molecules of the gas B have an additional vibrational mode, and have a mass $${m \over 4}$$ . The ratio of the specific heats ($$C_V^A$$ and $$C_V^B$$ ) of gas A and B, respectively is :
16
A particle moving with kinetic energy E has de Broglie wavelength $$\lambda $$. If energy $$\Delta $$E is added to its energy, the wavelength become $$\lambda $$/2. Value of $$\Delta $$E, is :
17
Consider a force $$\overrightarrow F = - x\widehat i + y\widehat j$$ . The work done by this force in moving a particle from point A(1, 0) to B(0, 1) along the line segment is : (all quantities are in SI units) JEE Main 2020 (Online) 9th January Morning Slot Physics - Work Power & Energy Question 93 English
18
A body A of mass m is moving in a circular orbit of radius R about a planet. Another body B of mass $${m \over 2}$$ collides with A with a velocity which is half $$\left( {{{\overrightarrow v } \over 2}} \right)$$ the instantaneous velocity$${\overrightarrow v }$$ of A. The collision is completely inelastic. Then, the combined body :
19
Consider a sphere of radius R which carries a uniform charge density $$\rho $$. If a sphere of radius $${{R \over 2}}$$ is carved out of it, as shown, the ratio $${{\left| {\overrightarrow {{E_A}} } \right|} \over {\left| {\overrightarrow {{E_B}} } \right|}}$$ of magnitude of electric field $${\overrightarrow {{E_A}} }$$ and $${\overrightarrow {{E_B}} }$$, respectively, at points A and B due to the remaining portion is : JEE Main 2020 (Online) 9th January Morning Slot Physics - Electrostatics Question 159 English
20
The electric fields of two plane electromagnetic plane waves in vacuum are given by
$$\overrightarrow {{E_1}} = {E_0}\widehat j\cos \left( {\omega t - kx} \right)$$ and
$$\overrightarrow {{E_2}} = {E_0}\widehat k\cos \left( {\omega t - ky} \right)$$
At t = 0, a particle of charge q is at origin with
a velocity $$\overrightarrow v = 0.8c\widehat j$$ (c is the speed of light in vacuum). The instantaneous force experienced by the particle is :
21
A long, straight wire of radius a carries a current distributed uniformly over its cross-section. The ratio of the magnetic fields due to the wire at distance $${a \over 3}$$ and 2$$a$$, respectively from the axis of the wire is :
22
Radiation, with wavelength 6561 $$\mathop A\limits^o $$ falls on a metal surface to produce photoelectrons. The electrons are made to enter a uniform magnetic field of 3 × 10–4 T. If the radius of the largest circular path followed by the electrons is 10 mm, the work function of the metal is close to :
23
The aperture diameter of a telescope is 5m. The separation between the moon and the earth is 4 × 105 km. With light of wavelength of 5500 $$\mathop A\limits^o $$, the minimum separation between objects on the surface of moon, so that they are just resolved, is close to :
24
A vessel of depth 2h is half filled with a liquid of refractive index $$2\sqrt 2 $$ and the upper half with another liquid of refractive index $$\sqrt 2 $$ . The liquids are immiscible. The apparent depth of the inner surface of the bottom of vessel will be :
25
A quantity f is given by $$f = \sqrt {{{h{c^5}} \over G}} $$ where c is speed of light, G universal gravitational constant and h is the Planck's constant. Dimension of f is that of :
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