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JEE Main 2021 (Online) 31st August Morning Shift

JEE Main / 30 questions

2026Tue, Aug 31, 2021 3:30 AM30 PYQs
1Alternating Current
In an ac circuit, an inductor, a capacitor and a resistor are connected in series with XL = R = XC. Impedance of this circuit is :
MCQ+4 / -12021
2Atoms And Nuclei
A sample of a radioactive nucleus A disintegrates to another radioactive nucleus B, which in turn disintegrates to some other stable nucleus C. Plot of a graph showing the variation of number of atoms of nucleus B versus time is :(Assume th...
MCQ+4 / -12021
3Capacitor
A capacitor of 50 \(\mu\)F is connected in a circuit as shown in figure. The charge on the upper plate of the capacitor is ______________\(\mu\)C.
INTEGER+4 / -12021
4Center Of Mass
A body of mass M moving at speed V0 collides elastically with a mass 'm' at rest. After the collision, the two masses move at angles \(\theta\)1 and \(\theta\)2 with respect to the initial direction of motion of the body of mass M. The larg...
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5Communication Systems
If the sum of the heights of transmitting and receiving antennas in the line of sight of communication is fixed at 160 m, then the maximum range of LOS communication is ___________ km. (Take radius of Earth = 6400 km)
INTEGER+4 / -12021
6Current Electricity
Consider a galvanometer shunted with 5\(\Omega\) resistance and 2% of current passes through it. What is the resistance of the given galvanometer ?
MCQ+4 / -12021
7Current Electricity
A square shaped wire with resistance of each side 3\(\Omega\) is bent to form a complete circle. The resistance between two diametrically opposite points of the circle in unit of \(\Omega\) will be ___________.
INTEGER+4 / -12021
8Current Electricity
The voltage drop across 15\(\Omega\) resistance in the given figure will be ______________ V.
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9Dual Nature Of Radiation
A moving proton and electron have the same de-Broglie wavelength. If K and P denote the K.E. and momentum respectively. Then choose the correct option :
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10Electromagnetic Induction
A small square loop of side 'a' and one turn is placed inside a larger square loop of side b and one turn (b >> a). The two loops are coplanar with their centres coinciding. If a current I is passed in the square loop of side 'b', then the ...
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11Electromagnetic Waves
The electric field in an electromagnetic wave is given by E = (50 NC\(-\)1) sin\(\omega\) (t \(-\) x/c)The energy contained in a cylinder of volume V is 5.5 \(\times\) 10\(-\)12 J. The value of V is _____________ cm3. (given \(\in\)0 = 8.8 ...
INTEGER+4 / -12021
12Electronic Devices
In the following logic circuit the sequence of the inputs A, B are (0, 0), (0, 1), (1, 0) and (1, 1). The output Y for this sequence will be :
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13Electronic Devices
Choose the correct waveform that can represent the voltage across R of the following circuit, assuming the diode is ideal one :
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14Electrostatics
Two particles A and B having charges 20\(\mu\)C and \(-\)5\(\mu\)C respectively are held fixed with a separation of 5 cm. At what position a third charged particle should be placed so that it does not experience a net electric force?
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15Geometrical Optics
An object is placed at the focus of concave lens having focal length f. What is the magnification and distance of the image from the optical centre of the lens?
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16Geometrical Optics
Two plane mirrors M1 and M2 are at right angle to each other shown. A point source 'P' is placed at 'a' and '2a' meter away from M1 and M2 respectively. The shortest distance between the images thus formed is : (Take \(\sqrt 5\) = 2.3)
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17Gravitation
The masses and radii of the earth and moon are (M1, R1) and (M2, R2) respectively. Their centres are at a distance 'r' apart. Find the minimum escape velocity for a particle of mass 'm' to be projected from the middle of these two masses :
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18Heat And Thermodynamics
A reversible engine has an efficiency of \({1 \over 4}\). If the temperature of the sink is reduced by 58\(^\circ\)C, its efficiency becomes double. Calculate the temperature of the sink :
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19Heat And Thermodynamics
For an ideal gas the instantaneous change in pressure 'p' with volume 'v' is given by the equation \({{dp} \over {dv}} = - ap\). If p = p0 at v =0 is the given boundary condition, then the maximum temperature one mole of gas can attain is...
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20Laws Of Motion
A car is moving on a plane inclined at 30\(^\circ\) to the horizontal with an acceleration of 10 ms\(-\)2 parallel to the plane upward. A bob is suspended by a string from the roof of the car. The angle in degrees which the string makes wit...
INTEGER+4 / -12021
21Magnetics
A coil having N turns is wound tightly in the form of a spiral with inner and outer radii 'a' and 'b' respectively. Find the magnetic field at centre, when a current I passes through coil:
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22Motion In A Plane
A helicopter is flying horizontally with a speed 'v' at an altitude 'h' has to drop a food packet for a man on the ground. What is the distance of helicopter from the man when the food packet is dropped?
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23Properties Of Matter
A uniform heavy rod of weight 10 kg ms\(-\)2, cross-sectional area 100 cm2 and length 20 cm is hanging from a fixed support. Young modulus of the material of the rod is 2 \(\times\) 1011 Nm\(-\)2. Neglecting the lateral contraction, find th...
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24Properties Of Matter
When a rubber ball is taken to a depth of __________m in deep sea, its volume decreases by 0.5%. (The bulk modulus of rubber = 9.8 \(\times\) 108 Nm\(-\)2, Density of sea water = 103 kgm\(-\)3, g = 9.8 m/s2)
INTEGER+4 / -12021
25Rotational Motion
Angular momentum of a single particle moving with constant speed along circular path :
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26Simple Harmonic Motion
A particle of mass 1 kg is hanging from a spring of force constant 100 Nm\(-\)1. The mass is pulled slightly downward and released so that it executes free simple harmonic motion with time period T. The time when the kinetic energy and pote...
INTEGER+4 / -12021
27Units And Measurements
Match List - I with List - II.



List - I

List - II




(a)
Torque
(i)
MLT\(^{ - 1}\)


(b)
Impulse
(ii)
MT\(^{ - 2}\)


(c)
Tension
(iii)
ML\(^{ 2}\)T$$^{ - 2}...
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28Units And Measurements
Which of the following equations is dimensionally incorrect?Where t = time, h = height, s = surface tension, \(\theta\) = angle, \(\rho\) = density, a, r = radius, g = acceleration due to gravity, v = volume, p = pressure, W = work done, T ...
MCQ+4 / -12021
29Waves
A wire having a linear mass density 9.0 \(\times\) 10\(-\)4 kg/m is stretched between two rigid supports with a tension of 900 N. The wire resonates at a frequency of 500 Hz. The next higher frequency at which the same wire resonates is 550...
INTEGER+4 / -12021
30Work Power And Energy
A block moving horizontally on a smooth surface with a speed of 40 ms\(-\)1 splits into two equal parts. If one of the parts moves at 60 ms\(-\)1 in the same direction, then the fractional change in the kinetic energy will be x : 4 where x ...
INTEGER+4 / -12021

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