A person is standing in an elevator. In which situation, he experiences weight loss?

Official solved question paper for Joint Entrance Examination (Main). Review all 90 questions, official answer keys, and detailed step-by-step solutions below, or attempt online with timer and negative marking.
A person is standing in an elevator. In which situation, he experiences weight loss?
An aluminium wire is stretched to make its length, 0.4% larger. The percentage change in resistance is :
In free space, an electromagnetic wave of 3 GHz frequency strikes over the edge of an object of size , where is the wavelength of the wave in free space. The phenomenon, which happens there will be :
A ball of mass 0.5 kg is dropped from the height of 10 m. The height, at which the magnitude of velocity becomes equal to the magnitude of acceleration due to gravity, is ________ m. [Use g = 10 m/s2]
The variation of acceleration due to gravity (g) with distance (r) from the center of the earth is correctly represented by :
(Given R = radius of earth)




An electron with speed v and a photon with speed c have the same de-Broglie wavelength. If the kinetic energy and momentum of electron are Ee and pe and that of photon are Eph and pph respectively. Which of the following is correct?
A fighter jet is flying horizontally at a certain altitude with a speed of 200 ms1. When it passes directly overhead an anti-aircraft gun, a bullet is fired from the gun, at an angle with the horizontal, to hit the jet. If the bullet speed is 400 m/s, the value of will be ___________.
A 10 , 20 mH coil carrying constant current is connected to a battery of 20 V through a switch. Now after switch is opened current becomes zero in 100 s. The average e.m.f. induced in the coil is ____________ V.
A 110 V, 50 Hz, AC source is connected in the circuit (as shown in figure). The current through the resistance 55 , at resonance in the circuit, will be __________ A.

A proton and an alpha particle of the same velocity enter in a uniform magnetic field which is acting perpendicular to their direction of motion. The ratio of the radii of the circular paths described by the alpha particle and proton is :
Time period of a simple pendulum in a stationary lift is 'T'. If the lift accelerates with vertically upwards then the time period will be :
(Where g = acceleration due to gravity)
The elongation of a wire on the surface of the earth is 104 m. The same wire of same dimensions is elongated by 6 105 m on another planet. The acceleration due to gravity on the planet will be ____________ ms2. (Take acceleration due to gravity on the surface of earth = 10 ms2)
Given below two statements : One is labelled as Assertion (A) and other is labelled as Reason (R).
Assertion (A) : Non-polar materials do not have any permanent dipole moment.
Reason (R) : When a non-polar material is placed in an electric field, the centre of the positive charge distribution of it's individual atom or molecule coincides with the centre of the negative charge distribution.
In the light of above statements, choose the most appropriate answer from the options given below.
A thermally insulated vessel contains an ideal gas of molecular mass M and ratio of specific heats 1.4. Vessel is moving with speed v and is suddenly brought to rest. Assuming no heat is lost to the surrounding and vessel temperature of the gas increases by :
(R = universal gas constant)
The elastic behaviour of material for linear stress and linear strain, is shown in the figure. The energy density for a linear strain of 5 104 is __________ kJ/m3. Assume that material is elastic upto the linear strain of 5 104.

The I-V characteristics of a p-n junction diode in forward bias is shown in the figure. The ratio of dynamic resistance, corresponding to forward bias voltage of 2 V and 4 V respectively, is :

As per the given circuit, the value of current through the battery will be ____________ A.

If Electric field intensity of a uniform plane electromagnetic wave is given as . Then magnetic intensity 'H' of this wave in Am1 will be :
[Given : Speed of light in vacuum ms1, Permeability of vacuum NA2]
A light ray is incident, at an incident angle 1, on the system of tow plane mirrors M1 and M2 having an inclination angle 75 between them (as shown in figure). After reflecting from mirror M1 it gets reflected back by the mirror M2 with an angle of reflection 30. The total deviation of the ray will be _____________ degree.

In a vernier callipers, each cm on the main scale is divided into 20 equal parts. If tenth vernier scale division coincides with nineth main scale division. Then the value of vernier constant will be _________ 102 mm.
The magnetic flux through a coil perpendicular to its plane is varying according to the relation Weber. If the resistance of the coil is 5 ohm, then the induced current through the coil at t = 2 s will be,
An expression for a dimensionless quantity P is given by ; where and are constants, x is distance; k is Boltzmann constant and t is the temperature. Then the dimensions of will be :
A ball is released from rest from point P of a smooth semi-spherical vessel as shown in figure. The ratio of the centripetal force and normal reaction on the ball at point Q is A while angular position of point Q is with respect to point P. Which of the following graphs represent the correct relation between A and when ball goes from Q to R?





An object is thrown vertically upwards. At its maximum height, which of the following quantity becomes zero?
How many alpha and beta particles are emitted when Uranium 92U238 decays to lead 82Pb206 ?
An ideal fluid of density 800 kgm3, flows smoothly through a bent pipe (as shown in figure) that tapers in cross-sectional area from a to . The pressure difference between the wide and narrow sections of pipe is 4100 Pa. At wider section, the velocity of fluid is ms1 for x = ___________. (Given g = 10 ms2)

Choose the correct statement for amplitude modulation :
Two capacitors having capacitance C1 and C2 respectively are connected as shown in figure. Initially, capacitor C1 is charged to a potential difference V volt by a battery. The battery is then removed and the charged capacitor C1 is now connected to uncharged capacitor C2 by closing the switch S. The amount of charge on the capacitor C2, after equilibrium, is :

The efficiency of a Carnot's engine, working between steam point and ice point, will be :
A thin circular ring of mass M and radius R is rotating with a constant angular velocity 2 rads1 in a horizontal plane about an axis vertical to its plane and passing through the center of the ring. If two objects each of mass m be attached gently to the opposite ends of a diameter of ring, the ring will then rotate with an angular velocity (in rads1).
If the radius of the 3rd Bohr's orbit of hydrogen atom is r3 and the radius of 4th Bohr's orbit is r4. Then :
Compound 'P' on nitration with dil. HNO3 yields two isomers (A) and (B). These isomers can be separated by steam distillation. Isomers (A) and (B) show the intramolecular and intermolecular hydrogen bonding respectively. Compound (P) on reaction with conc. HNO3 yields a yellow compound 'C', a strong acid. The number of oxygen atoms is present in compound 'C' _____________.
Among the following structures, which will show the most stable enamine formation? (Where Me is CH3)




50 mL of 0.1 M CH3COOH is being titrated against 0.1 M NaOH. When 25 mL of NaOH has been added, the pH of the solution will be _____________ 102. (Nearest integer)
(Given : pKa (CH3COOH) = 4.76)
log 2 = 0.30
log 3 = 0.48
log 5 = 0.69
log 7 = 0.84
log 11 = 1.04
Given below are two statements :
Statement I : According to Ellingham diagram, any metal oxide with higher G is more stable than the one with lower G.
Statement II : The metal involved in the formation of oxide placed lower in the Ellingham diagram can reduce the oxide of a metal placed higher in the diagram.
In the light of the above statements, choose the most appropriate answer from the options given below :
Consider the following reaction :
A + alkali B (Major Product)
If B is an oxoacid of phosphorus with no P-H bond, then A is :
For complete combustion of methanol
CH3OH(I) + O2(g) CO2(g) + 2H2O(I)
the amount of heat produced as measured by bomb calorimeter is 726 kJ mol1 at 27C. The enthalpy of combustion for the reaction is x kJ mol1, where x is ___________. (Nearest integer)
(Given : R = 8.3 JK1 mol1)
The number of oxygens present in a nucleotide formed from a base, that is present only in RNA is ___________.
A 0.5 percent solution of potassium chloride was found to freeze at 0.24C. The percentage dissociation of potassium chloride is ______________. (Nearest integer)
(Molal depression constant for water is 1.80 K kg mol1 and molar mass of KCl is 74.6 g mol1)
On complete combustion 0.30 g of an organic compound gave 0.20 g of carbon dioxide and 0.10 g of water. The percentage of carbon in the given organic compound is _____________. (Nearest integer)
The of different types of half cells are as follows:
| A | B | C | D |
|---|---|---|---|
(Where E is the electromotive force)
Which of the above half cells would be preferred to be used as reference electrode?
(C7H5O2)2 [X] 2C6H5 + 2CO2
Consider the above reaction and identify the intermediate 'X'




Consider the following reaction:
The dihedral angle in product A in its solid phase at 110 K is :
Which will have the highest enol content?





Consider the above reaction sequence and identify the product B.




A commercially sold conc. HCl is 35% HCl by mass. If the density of this commercial acid is 1.46 g/mL, the molarity of this solution is:
(Atomic mass : Cl = 35.5 amu, H = 1 amu)
A chemical which stimulates the secretion of pepsin is :
The correct order of melting point is :
The correct order of melting points of hydrides of group 16 elements is :
Polar stratospheric clouds facilitate the formation of :
Which statement is not true with respect to nitrate ion test?
Consider the ions/molecule
O, O2, O, O
For increasing bond order the correct option is :
A flask is filled with equal moles of A and B. The half lives of A and B are 100 s and 50 s respectively and are independent of the initial concentration. The time required for the concentration of A to be four times that of B is ___________ s.
(Given : ln 2 = 0.693)
The spin-only magnetic moment value of an octahedral complex among CoCl3.4NH3, NiCl2.6H2O and PtCl4.2HCl, which upon reaction with excess of AgNO3 gives 2 moles of AgCl is ___________ B.M. (Nearest integer)
Given below are two statements :
Statement I : In 'Lassaigne's Test', when both nitrogen and sulphur are present in an organic compound, sodium thiocyanate is formed.
Statement II : If both nitrogen and sulphur are present in an organic compound, then the excess of sodium used in sodium fusion will decompose the sodium thiocyanate formed to give NaCN and Na2S.
In the light of the above statements, choose the most appropriate answer from the options given below :
The spin-only magnetic moment value of the most basic oxide of vanadium among V2O3, V2O4 and V2O5 is _____________ B.M. (Nearest integer)
An evacuated glass vessel weighs 40.0 g when empty, 135.0 g when filled with a liquid of density 0.95 g mL1 and 40.5 g when filled with an ideal gas at 0.82 atm at 250 K. The molar mass of the gas in g mol1 is :
(Given : R = 0.082 L atm K1 mol1)
Choose the correct stability order of group 13 elements in their + 1 oxidation state :
Which of the following sets are correct regarding polymer?
(A) Copolymer : Buna-S
(B) Condensation polymer : Nylon-6,6
(C) Fibres : Nylon-6,6
(D) Thermosetting polymer : Terylene
(E) Homopolymer : Buna-N
Choose the correct answer from given options below :
2.0 g of H2 gas is adsorbed on 2.5 g of platinum powder at 300 K and 1 bar pressure. The volume of the gas adsorbed per gram of the adsorbent is __________ mL.
(Given : R = 0.083 L bar K1 mol1)
Let and . Then A B is :
If the two lines and are perpendicular, then an angle between the lines l2 and is :
Let the common tangents to the curves and intersect at the point Q. Let an ellipse, centered at the origin O, has lengths of semi-minor and semi-major axes equal to OQ and 6, respectively. If e and l respectively denote the eccentricity and the length of the latus rectum of this ellipse, then is equal to ______________.
Let and . Then A + B is equal to _____________.
Let A be a 3 3 invertible matrix. If |adj (24A)| = |adj (3 adj (2A))|, then |A|2 is equal to :
Let the plane 2x + 3y + z + 20 = 0 be rotated through a right angle about its line of intersection with the plane x 3y + 5z = 8. If the mirror image of the point in the rotated plane is B(a, b, c), then :
If , then is equal to __________.
Let , . If [a, b] is the range of the function f, then 4a b is equal to :
Let a biased coin be tossed 5 times. If the probability of getting 4 heads is equal to the probability of getting 5 heads, then the probability of getting atmost two heads is :
The area bounded by the curve y = |x2 9| and the line y = 3 is :
is equal to :
There are ten boys B1, B2, ......., B10 and five girls G1, G2, ........, G5 in a class. Then the number of ways of forming a group consisting of three boys and three girls, if both B1 and B2 together should not be the members of a group, is ___________.
Let R be the point (3, 7) and let P and Q be two points on the line x + y = 5 such that PQR is an equilateral triangle. Then the area of PQR is :
The value of the integral
is equal to __________.
The sum of the absolute minimum and the absolute maximum values of the
function f(x) = |3x x2 + 2| x in the interval [1, 2] is :
Let the solution curve y = y(x) of the differential equation
pass through the origin. Then y(2) is equal to _____________.
The ordered pair (a, b), for which the system of linear equations
3x 2y + z = b
5x 8y + 9z = 3
2x + y + az = 1
has no solution, is :
Let . If for all n N, then is equal to :
If and , then the value of is :
Let A = {n N : H.C.F. (n, 45) = 1} and
Let B = {2k : k {1, 2, ......., 100}}. Then the sum of all the elements of A B is ____________.
Let S be the set of all the natural numbers, for which the line is a tangent to the curve at the point (a, b), ab 0. Then :
Let the normal at the point on the parabola y2 = 6x pass through the point (5, 8). If the tangent at P to the parabola intersects its directrix at the point Q, then the ordinate of the point Q is :
Let f, g : R R be two real valued functions defined as f(x) = \left\{ {\matrix{ { - |x + 3|} & , & {x < 0} \cr {{e^x}} & , & {x \ge 0} \cr } } \right. and g(x) = \left\{ {\matrix{ {{x^2} + {k_1}x} & , & {x < 0} \cr {4x + {k_2}} & , & {x \ge 0} \cr } } \right., where k1 and k2 are real constants. If (gof) is differentiable at x = 0, then (gof) ( 4) + (gof) (4) is equal to :
Let f(x) = max {|x + 1|, |x + 2|, ....., |x + 5|}. Then is equal to __________.
The remainder when (2021)2023 is divided by 7 is :
The mean of the numbers a, b, 8, 5, 10 is 6 and their variance is 6.8. If M is the mean deviation of the numbers about the mean, then 25 M is equal to :
Let , {, } be such that p q ((p q) r) is a tautology. Then (p q) r is logically equivalent to :
Let . Let , x S, be the solution curve of the differential equation . If the sum of abscissas of all the points of intersection of the curve y = y(x) with the curve is , then k is equal to _____________.
The sum of the cubes of all the roots of the equation
is _________.
Let C be a circle passing through the points A(2, 1) and B(3, 4). The line segment AB s not a diameter of C. If r is the radius of C and its centre lies on the circle , then r2 is equal to :