JEE Main 2020 (Online) 3rd September Morning Slot
Paper was held on Thu, Sep 3, 2020 3:30 AM
View Questions

Chemistry

1
An acidic buffer is obtained on mixing :
2
The Kjeldahl method of Nitrogen estimation fails for which of the following reaction products? JEE Main 2020 (Online) 3rd September Morning Slot Chemistry - Compounds Containing Nitrogen Question 162 English
3
Which one of the following compounds possesses the most acidic hydrogen?
4
The complex that can show optical activity is :
5
It is true that :
6
The atomic number of the element unnilennium is :
7
The photoelectric current from Na (Work function, w0 = 2.3 eV) is stopped by the output voltage of the cell
Pt(s) | H2 (g, 1 Bar) | HCl (aq., pH =1) | AgCl(s) | Ag(s).
The pH of aq. HCl required to stop the photoelectric current form K(w0 = 2.25 eV), all other conditions remaining the same, is _______ $$ \times $$ 10-2 (to the nearest integer).

Given, 2.303$${{RT} \over F}$$ = 0.06 V;
$$E_{AgCl|Ag|C{l^ - }}^0$$ = 0.22 V
8
The total number of monohalogenated organic products in the following (including stereoisomers) reaction is ______. JEE Main 2020 (Online) 3rd September Morning Slot Chemistry - Hydrocarbons Question 93 English
9
The volume strength of 8.9 M H2O2 solution calculated at 273 K and 1 atm is ______. (R = 0.0821 L atm K-1 mol-1) (rounded off ot the nearest integer)
10
The mole fraction of glucose (C6H12O6 ) in an aqueous binary solution is 0.1. The mass percentage of water in it, to the nearest integer, is _______.
11
Let CNaCl and CBaSO4 be the conductances (in S) measured for saturated aqueous solutions of NaCl and BaSO4, respectively, at a temperature T. Which of the following is false?
12
The mechanism of SN1 reaction is given as : JEE Main 2020 (Online) 3rd September Morning Slot Chemistry - Haloalkanes and Haloarenes Question 107 English
A student writes general characteristics based on the given mechanism as :
(a) The reaction is favoured by weak nucleophiles.
(b) R+ would be easily formed if the substituents are bulky.
(c) The reaction is accompanied by racemization.
(d) The reaction is favoured by non-polar solvents.
13
Henry’s constant (in kbar) for four gases $$\alpha $$, $$\beta $$, $$\gamma $$ and $$\delta $$ in water at 298 K is given below :

$$\alpha $$ $$\beta $$ $$\gamma $$ $$\delta $$
KH 50 2 2 $$ \times $$ 10-5 0.5

(density of water = 103 kg m-3 at 298 K)
This table implies that :
14
The electronic spectrum of [Ti(H2O)6]3+ shows a single broad peak with a maximum at 20,300 cm-1 . The crystal field stabilization energy (CFSE) of the complex ion, in kJ mol-1, is :
15
An organic compound [A], molecular formula C10H20O2 was hydrolyzed with dilute sulphuric acid to give a carboxylic acid [B] and an alcohol [C]. Oxidation of [C] with
CrO3 - H2SO4 produced [B]. Which of the following strucutres are not possible for [A]?
16
Glycerol is separated in soap industries by :
17
Of the species, NO, NO+, NO2+ and NO- , the one with minimum bond strength is :
18
Which of the following compounds produces an optically inactive compound on hydrogenation?

Mathematics

1
For the frequency distribution :
Variate (x) :      x1   x2   x3 ....  x15
Frequency (f) : f1    f2   f3 ...... f15
where 0 < x1 < x2 < x3 < ... < x15 = 10 and
$$\sum\limits_{i = 1}^{15} {{f_i}} $$ > 0, the standard deviation cannot be :
2
2$$\pi $$ - $$\left( {{{\sin }^{ - 1}}{4 \over 5} + {{\sin }^{ - 1}}{5 \over {13}} + {{\sin }^{ - 1}}{{16} \over {65}}} \right)$$ is equal to :
3
Let [t] denote the greatest integer $$ \le $$ t. If for some
$$\lambda $$ $$ \in $$ R - {1, 0}, $$\mathop {\lim }\limits_{x \to 0} \left| {{{1 - x + \left| x \right|} \over {\lambda - x + \left[ x \right]}}} \right|$$ = L, then L is equal to :
4
The solution curve of the differential equation,

(1 + e-x)(1 + y2)$${{dy} \over {dx}}$$ = y2,

which passes through the point (0, 1), is :
5
If $$\alpha $$ and $$\beta $$ are the roots of the equation
x2 + px + 2 = 0 and $${1 \over \alpha }$$ and $${1 \over \beta }$$ are the
roots of the equation 2x2 + 2qx + 1 = 0, then
$$\left( {\alpha - {1 \over \alpha }} \right)\left( {\beta - {1 \over \beta }} \right)\left( {\alpha + {1 \over \beta }} \right)\left( {\beta + {1 \over \alpha }} \right)$$ is equal to :
6
If the number of integral terms in the expansion
of (31/2 + 51/8)n is exactly 33, then the least value of n is :
7
If $$\Delta $$ = $$\left| {\matrix{ {x - 2} & {2x - 3} & {3x - 4} \cr {2x - 3} & {3x - 4} & {4x - 5} \cr {3x - 5} & {5x - 8} & {10x - 17} \cr } } \right|$$ =

Ax3 + Bx2 + Cx + D, then B + C is equal to :
8
The value of (2.1P0 – 3.2P1 + 4.3P2 .... up to 51th term)
+ (1! – 2! + 3! – ..... up to 51th term) is equal to :
9
The function, f(x) = (3x – 7)x2/3, x $$ \in $$ R, is increasing for all x lying in :
10
If y2 + loge (cos2x) = y,
$$x \in \left( { - {\pi \over 2},{\pi \over 2}} \right)$$, then :
11
$$\int\limits_{ - \pi }^\pi {\left| {\pi - \left| x \right|} \right|dx} $$ is equal to :
12
Consider the two sets :
A = {m $$ \in $$ R : both the roots of
x2 – (m + 1)x + m + 4 = 0 are real}
and B = [–3, 5).
Which of the following is not true?
13
Let P be a point on the parabola, y2 = 12x and N be the foot of the perpendicular drawn from P on the axis of the parabola. A line is now drawn through the mid-point M of PN, parallel to its axis which meets the parabola at Q. If the y-intercept of the line NQ is $${4 \over 3}$$, then :
14
The area (in sq. units) of the region

{ (x, y) : 0 $$ \le $$ y $$ \le $$ x2 + 1, 0 $$ \le $$ y $$ \le $$ x + 1,

$${1 \over 2}$$ $$ \le $$ x $$ \le $$ 2 } is :
15
A hyperbola having the transverse axis of length $$\sqrt 2 $$ has the same foci as that of the ellipse 3x2 + 4y2 = 12, then this hyperbola does not pass through which of the following points?
16
If the first term of an A.P. is 3 and the sum of its first 25 terms is equal to the sum of its next 15 terms, then the common difference of this A.P. is :
17
The lines
$$\overrightarrow r = \left( {\widehat i - \widehat j} \right) + l\left( {2\widehat i + \widehat k} \right)$$ and
$$\overrightarrow r = \left( {2\widehat i - \widehat j} \right) + m\left( {\widehat i + \widehat j + \widehat k} \right)$$
18
A dice is thrown two times and the sum of the scores appearing on the die is observed to be a multiple of 4. Then the conditional probability that the score 4 has appeared atleast once is :
19
If $${\left( {{{1 + i} \over {1 - i}}} \right)^{{m \over 2}}} = {\left( {{{1 + i} \over {1 - i}}} \right)^{{n \over 3}}} = 1$$, (m, n $$ \in $$ N) then the greatest common divisor of the least values of m and n is _______ .
20
The diameter of the circle, whose centre lies on the line x + y = 2 in the first quadrant and which touches both the lines x = 3 and y = 2, is _______ .
21
If $$\mathop {\lim }\limits_{x \to 0} \left\{ {{1 \over {{x^8}}}\left( {1 - \cos {{{x^2}} \over 2} - \cos {{{x^2}} \over 4} + \cos {{{x^2}} \over 2}\cos {{{x^2}} \over 4}} \right)} \right\}$$ = 2-k

then the value of k is _______ .
22
The value of $${\left( {0.16} \right)^{{{\log }_{2.5}}\left( {{1 \over 3} + {1 \over {{3^2}}} + ....to\,\infty } \right)}}$$ is equal to ______.
23
Let A = $$\left[ {\matrix{ x & 1 \cr 1 & 0 \cr } } \right]$$, x $$ \in $$ R and A4 = [aij].
If a11 = 109, then a22 is equal to _______ .

Physics

1
Two isolated conducting spheres S1 and S2 of radius $${2 \over 3}R$$ and $${1 \over 3}R$$ have 12 $$\mu $$C and –3 $$\mu $$C charges, respectively, and are at a large distance from each other. They are now connected by a conducting wire. A long time after this is done the charges on S1 and S2 are respectively :
2
An observer can see through a small hole on the side of a jar (radius 15 cm) at a point at height of 15 cm from the bottom (see figure). The hole is at a height of 45 cm. When the jar is filled with a liquid up to a height of 30 cm the same observer can see the edge at the bottom of the jar. If the refractive index of the liquid is N/100, where N is an integer, the value of N is _____. JEE Main 2020 (Online) 3rd September Morning Slot Physics - Geometrical Optics Question 146 English
3
When a long glass capillary tube of radius 0.015 cm is dipped in a liquid, the liquid rises to a height of 15 cm within it. If the contact angle between the liquid and glass to close to 0o, the surface tension of the liquid, in milliNewton m–1, is [$$\rho $$(liquid) = 900 kgm–3, g = 10 ms–2]
(Give answer in closest integer) _____.
4
A person of 80 kg mass is standing on the rim of a circular platform of mass 200 kg rotating about its axis at 5 revolutions per minute (rpm). The person now starts moving towards the centre of the platform. What will be the rotational speed (in rpm) of the platform when the person reaches its centre _________.
5
A cricket ball of mass 0.15 kg is thrown vertically up by a bowling machine so that it rises to a maximum height of 20 m after leaving the machine. If the part pushing the ball applies a constant force F on the ball and moves horizontally a distance of 0.2 m while launching the ball, the value of F (in N) is (g = 10 ms–2) ____.
6
A bakelite beaker has volume capacity of 500 cc at 30oC. When it is partially filled with Vm volume (at 30oC) of mercury, it is found that the unfilled volume of the beaker remains constant as temperature is varied. If $$\gamma $$(beaker) = 6 × 10–6 oC–1 and $$\gamma $$(mercury) = 1.5 × 10–4 oC–1, where $$\gamma $$ is the coefficient of volume expansion, then Vm (in cc) is close to ____.
7
JEE Main 2020 (Online) 3rd September Morning Slot Physics - Heat and Thermodynamics Question 273 English Consider a gas of triatomic molecules. The molecules are assumed to be triangular and made of massless rigid rods whose vertices are occupied by atoms. The internal energy of a mole of the gas at temperature T is :
8
Magnitude of magnetic field (in SI units) at the centre of a hexagonal shape coil of side 10 cm, 50 turns and carrying current I (Ampere) in units of $${{{\mu _0}I} \over \pi }$$ is :
9
In a Young’s double slit experiment, light of 500 nm is used to produce an interference pattern. When the distance between the slits is 0.05 mm, the angular width (in degree) of the fringes formed on the distance screen is close to
10
A block of mass m = 1 kg slides with velocity v = 6 m/s on a frictionless horizontal surface and collides with a uniform vertical rod and sticks to it as shown. The rod is pivoted about O and swings as a result of the collision making angle $$\theta $$ before momentarily coming to rest. If the rod has mass M = 2 kg, and length $$l$$ = 1 m, the value of $$\theta $$ is approximately :
(take g = 10 m/s2) JEE Main 2020 (Online) 3rd September Morning Slot Physics - Center of Mass and Collision Question 70 English
11
A uniform thin rope of length 12 m and mass 6 kg hangs vertically from a rigid support and a block of mass 2 kg is attached to its free end. A transverse short wavetrain of wavelength 6 cm is produced at the lower end of the rope. What is the wavelength of the wavetrain (in cm) when it reaches the top of the rope ?
12
When a diode is forward biased, it has a voltage drop of 0.5 V. The safe limit of current through the diode is 10 mA. If a battery of emf 1.5 V is used in the circuit, the value of minimum resistance to be connected in series with the diode so that the current does not exceed the safe limit is
13
An elliptical loop having resistance R, of semi major axis a, and semi minor axis b is placed in magnetic field as shown in the figure. If the loop is rotated about the x-axis with angular frequency $$\omega $$, the average power loss in the loop due to Joule heating is : JEE Main 2020 (Online) 3rd September Morning Slot Physics - Electromagnetic Induction Question 83 English
14
When the wavelength of radiation falling on a metal is changed from 500 nm to 200 nm, the maximum kinetic energy of the photoelectrons becomes three times larger. The work function of the metal is close to :
15
In the circuit shown in the figure, the total charge is 750 $$\mu $$C and the voltage across capacitor C2 is 20 V. Then the charge on capacitor C2 is : JEE Main 2020 (Online) 3rd September Morning Slot Physics - Capacitor Question 98 English
16
A satellite is moving in a low nearly circular orbit around the earth. Its radius is roughly equal to that of the earth’s radius Re . By firing rockets attached to it, its speed is instantaneously increased in the direction of its motion so that it become $$\sqrt {{3 \over 2}} $$ times larger. Due to this the farthest distance from the centre of the earth that the satellite reaches is R. Value of R is :
17
A balloon filled with helium (32oC and 1.7 atm.) bursts. Immediately afterwards the expansion of helium can be considered as
18
Pressure inside two soap bubbles are 1.01 and 1.02 atmosphere, respectively. The ratio of their volumes is :
19
A 750 Hz, 20 V (rms) source is connected to a resistance of 100 $$\Omega $$, an inductance of 0.1803 H and a capacitance of 10 $$\mu $$F all in series. The time in which the resistance (heat capacity 2 J/oC) will get heated by 10oC. (assume no loss of heat to the surroudnings) is close to :
20
A charged particle carrying charge 1 $$\mu $$C is moving
with velocity $$\left( {2\widehat i + 3\widehat j + 4\widehat k} \right)$$ ms–1. If an external
magnetic field of $$\left( {5\widehat i + 3\widehat j - 6\widehat k} \right)$$× 10–3 T exists in the region where the particle is moving then the
force on the particle is $$\overrightarrow F $$ × 10–9 N. The vector $$\overrightarrow F $$ is :
21
The magnetic field of a plane electromagnetic wave is
$$\overrightarrow B = 3 \times {10^{ - 8}}\sin \left[ {200\pi \left( {y + ct} \right)} \right]\widehat i$$ T
where c = 3 $$ \times $$ 108 ms–1 is the speed of light. The corresponding electric field is :
22
Moment of inertia of a cylinder of mass M, length L and radius R about an axis passing through its centre and perpendicular to the axis of the cylinder is
I = $$M\left( {{{{R^2}} \over 4} + {{{L^2}} \over {12}}} \right)$$. If such a cylinder is to be made for a given mass of a material, the ratio $${L \over R}$$ for it to have minimum possible I is
23
Model a torch battery of length $$l$$ to be made up of a thin cylindrical bar of radius ‘a’ and a concentric thin cylindrical shell of radius ‘b’ filled in between with an electrolyte of resistivity $$\rho $$ (see figure). If the battery is connected to a resistance of value R, the maximum Joule heating in R will take place for : JEE Main 2020 (Online) 3rd September Morning Slot Physics - Current Electricity Question 218 English
24
Using screw gauge of pitch 0.1 cm and 50 divisions on its circular scale, the thickness of an object is measured. It should correctly be recorded as
EXAM MAP
Medical
NEETAIIMS
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
Civil Services
UPSC Civil Service
Defence
NDA
Staff Selection Commission
SSC CGL Tier I
CBSE
Class 12