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JEE Main 2021 (Online) 18th March Morning Shift

JEE Main / 30 questions

2026Thu, Mar 18, 2021 3:30 AM30 PYQs
1Alternating Current
In a series LCR resonance circuit, if we change the resistance only, from a lower to higher value :
MCQ+4 / -12021
2Alternating Current
An AC source rated 220 V, 50 Hz is connected to a resistor. The time taken by the current to change from its maximum to the rms value is :
MCQ+4 / -12021
3Atoms And Nuclei
Imagine that the electron in a hydrogen atom is replaced by a muon (\(\mu\)). The mass of muon particle is 207 times that of an electron and charge is equal to the charge of an electron. The ionization potential of this hydrogen atom will b...
MCQ+4 / -12021
4Atoms And Nuclei
A radioactive sample disintegrates via two independent decay processes having half lives \(T_{1/2}^{(1)}\) and \(T_{1/2}^{(2)}\) respectively. The effective half-life T1/2 of the nuclei is :
MCQ+4 / -12021
5Capacitor
A parallel plate capacitor has plate area 100 m2 and plate separation of 10 m. The space between the plates is filled up to a thickness 5 m with a material of dielectric constant of 10. The resultant capacitance of the system is 'x' pF.The ...
INTEGER+4 / -12021
6Capacitor
The circuit shown in the figure consists of a charged capacitor of capacity 3 \(\mu\)F and a charge of \(\mu\)C. At time t = 0, when the key is closed, the value of current flowing through the 5 M\(\Omega\) resistor is 'x' \(\mu\)-A. The va...
INTEGER+4 / -12021
7Center Of Mass
A ball of mass 10 kg moving with a velocity 10\(\sqrt 3\) m/s along the x-axis, hits another ball of mass 20 kg which is at rest. After the collision, first ball comes to rest while the second ball disintegrates into two equal pieces. One ...
INTEGER+4 / -12021
8Communication Systems
Match List - I with List - II.List - I(a) 10 km height over earth's surface(b) 70 km height over earth's surface(c) 180 km height over earth's surface(d) 270 km height over earth's surfaceList - II(i) Thermosphere(ii) Mesosphere(iii) Strato...
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9Current Electricity
In the experiment of Ohm's law, a potential difference of 5.0 V is applied across the end of a conductor of length 10.0 cm and diameter of 5.00 mm. The measured current in the conductor is 2.00 A. The maximum permissible percentage error in...
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10Current Electricity
The voltage across the 10\(\Omega\) resistor in the given circuit is x volt.The value of 'x' to the nearest integer is _________.
INTEGER+4 / -12021
11Dual Nature Of Radiation
A particle is travelling 4 time as fast as an electron. Assuming the ratio of de-Broglie wavelength of a particle to that of electron is 2 : 1, the mass of the particle is :
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12Electromagnetic Waves
A plane electromagnetic wave of frequency 100 MHz is travelling in vacuum along the x-direction. At a particular point in space and time, \(\overrightarrow B = 2.0 \times {10^{ - 8}}\widehat kT\). (where, \(\widehat k\) is unit vector alon...
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13Electronic Devices
An npn transistor operates as a common emitter amplifier with a power gain of 106. The input circuit resistance is 100\(\Omega\) and the output load resistance is 10 K\(\Omega\). The common emitter current gain '\(\beta\)' will be ________....
INTEGER+4 / -12021
14Electrostatics
An oil drop of radius 2 mm with a density 3g cm\(-\)3 is held stationary under a constant electric field 3.55 \(\times\) 105 V m\(-\)1 in the Millikan's oil drop experiment. What is the number of excess electrons that the oil drop will poss...
MCQ+4 / -12021
15Geometrical Optics
Your friend is having eye sight problem. She is not able to see clearly a distant uniform window mesh and it appears to her as non-uniform and distorted. The doctor diagnosed the problem as :
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16Gravitation
The time period of a satellite in a circular orbit of radius R is T. The period of another satellite in a circular orbit of radius 9R is :
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17Heat And Thermodynamics
The P-V diagram of a diatomic ideal gas system going under cyclic process as shown in figure. The work done during an adiabatic process CD is (use \(\gamma\) = 1.4) :
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18Heat And Thermodynamics
What will be the average value of energy along one degree of freedom for an ideal gas in thermal equilibrium at a temperature T? (kB is Boltzmann constant)
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19Laws Of Motion
A bullet of mass 0.1 kg is fired on a wooden block to pierce through it, but it stops after moving a distance of 50 cm into it. If the velocity of bullet before hitting the wood is 10 m/s and it slows down with uniform deceleration, then th...
INTEGER+4 / -12021
20Magnetics
A loop of flexible wire of irregular shape carrying current is placed in an external magnetic field. Identify the effect of the field on the wire.
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21Magnetics
Four identical long solenoids A, B, C and D are connected to each other as shown in the figure. If the magnetic field at the center of A is 3T, the field at the center of C would be : (Assume that the magnetic field is confined with in the ...
MCQ+4 / -12021
22Motion In A Plane
A person is swimming with a speed of 10 m/s at an angle of 120\(^\circ\) with the flow and reaches to a point directly opposite on the other side of the river. The speed of the flow is 'x' m/s. The value of 'x' to the nearest integer is ___...
INTEGER+4 / -12021
23Motion In A Straight Line
The position, velocity and acceleration of a particle moving with a constant acceleration can be represented by :
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24Properties Of Matter
Two separate wires A and B are stretched by 2 mm and 4 mm respectively, when they are subjected to a force of 2 N. Assume that both the wires are made up of same material and the radius of wire B is 4 times that of the radius of wire A. The...
INTEGER+4 / -12021
25Rotational Motion
A thin circular ring of mass M and radius r is rotating about its axis with an angular speed \(\omega\). Two particles having mass m each are now attached at diametrically opposite points. The angular speed of the ring will become :
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26Simple Harmonic Motion
The time period of a simple pendulum is given by \(T = 2\pi \sqrt {{l \over g}}\). The measured value of the length of pendulum is 10 cm known to a 1mm accuracy. The time for 200 oscillations of the pendulum is found to be 100 second using...
MCQ+4 / -12021
27Simple Harmonic Motion
A particle performs simple harmonic motion with a period of 2 second. The time taken by the particle to cover a displacement equal to half of its amplitude from the mean position is \({1 \over a}\)s. The value of 'a' to the nearest integer ...
INTEGER+4 / -12021
28Wave Optics
In Young's double slit arrangement, slits are separated by a gap of 0.5 mm, and the screen is placed at a distance of 0.5 m from them. The distance between the first and the third bright fringe formed when the slits are illuminated by a mon...
MCQ+4 / -12021
29Work Power And Energy
As shown in the figure, a particle of mass 10 kg is placed at a point A. When the particle is slightly displaced to its right, it starts moving and reaches the point B. The speed of the particle at B is x m/s. (Take g = 10 m/s2)The value of...
INTEGER+4 / -12021
30Work Power And Energy
A constant power delivering machine has towed a box, which was initially at rest, along a horizontal straight line. The distance moved by the box in time 't' is proportional to :-
MCQ+4 / -12021

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