JEE Main 2021 (Online) 17th March Evening Shift
JEE Main / 30 questions
2026Wed, Mar 17, 2021 9:30 AM30 PYQs
1Alternating Current
Match List - I with List - II
List - I
List - II
(a)
Phase difference between current and voltage in a purely resistive AC circuit
(i)
\({\pi \over 2}\); current leads voltage
(b)
...
List - I
List - II
(a)
Phase difference between current and voltage in a purely resistive AC circuit
(i)
\({\pi \over 2}\); current leads voltage
(b)
...
MCQ+4 / -12021
2Alternating Current
What happens to the inductive reactance and the current in a purely inductive circuit if the frequency is halved?
MCQ+4 / -12021
3Atoms And Nuclei
A particle of mass m moves in a circular orbit in a central potential field U(r) = U0r4. If Bohr's quantization conditions are applied, radii of possible orbitals rn vary with \({n^{{1 \over \alpha }}}\), where \(\alpha\) is ____________.
INTEGER+4 / -12021
4Atoms And Nuclei
The atomic hydrogen emits a line spectrum consisting of various series. Which series of hydrogen atomic spectra is lying in the visible region?
MCQ+4 / -12021
5Capacitor
A 2\(\mu\)F capacitor C1 is first charged to a potential difference of 10V using a battery. Then the battery is removed and the capacitor is connected to an uncharged capacitor C2 of 8 \(\mu\)F. The charge in C2 on equilibrium condition is ...
INTEGER+4 / -12021
6Center Of Mass
The disc of mass M with uniform surface mass density \(\sigma\) is shown in the figure. The centre of mass of the quarter disc (the shaded area) is at the position \({x \over 3}{a \over \pi },{x \over 3}{a \over \pi }\) where x is _________...
INTEGER+4 / -12021
7Center Of Mass
Two identical blocks A and B each of mass m resting on the smooth horizontal floor are connected by a light spring of natural length L and spring constant K. A third block C of mass m moving with a speed v along the line joining A and B col...
MCQ+4 / -12021
8Communication Systems
A carrier signal C(t) = 25 sin(2.512 \(\times\) 1010t) is amplitude modulated by a message signal m(t) = 5 sin(1.57 \(\times\) 108t) and transmitted through an antenna. What will be the bandwidth of the modulated signal?
MCQ+4 / -12021
9Current Electricity
The four arms of a Wheatstone bridge have resistances as shown in the figure. A galvanometer of 15\(\Omega\) resistance is connected across BD. Calculate the current through the galvanometer when a potential difference of 10V is maintained ...
MCQ+4 / -12021
10Current Electricity
Two cells of emf 2E and E with internal resistance r1 and r2 respectively are connected in series to an external resistor R (see figure). The value of R, at which the potential difference across the terminals of the first cell becomes zero ...
MCQ+4 / -12021
11Dual Nature Of Radiation
Two identical photocathodes receive the light of frequencies f1 and f2 respectively. If the velocities of the photo-electrons coming out are v1 and v2 respectively, then
MCQ+4 / -12021
12Electromagnetic Waves
Seawater at a frequency f = 9 \(\times\) 102 Hz, has permittivity \(\varepsilon\) = 80\(\varepsilon\)0 and resistivity \(\rho\) = 0.25 \(\Omega\)m. Imagine a parallel plate capacitor is immersed in seawater and is driven by an alternating...
INTEGER+4 / -12021
13Electromagnetic Waves
The electric field intensity produced by the radiation coming from a 100 W bulb at a distance of 3 m is E. The electric field intensity produced by the radiation coming from 60W at the same distance is \(\sqrt {{x \over 5}}\)E. Where the v...
INTEGER+4 / -12021
14Electronic Devices
Which one of the following will be the output of the given circuit?
MCQ+4 / -12021
15Electrostatics
The electric field in a region is given by \(\overrightarrow E = {2 \over 5}{E_0}\widehat i + {3 \over 5}{E_0}\widehat j\) with \({E_0} = 4.0 \times {10^3}{N \over C}\). The flux of this field through a rectangular surface area 0.4 m2 para...
INTEGER+4 / -12021
16Geometrical Optics
The image of an object placed in air formed by a convex refracting surface is at a distance of 10 m behind the surface. The image is real and is at \({{{2^{rd}}} \over 3}\) of the distance of the object from the surface. The wavelength of l...
INTEGER+4 / -12021
17Gravitation
A geostationary satellite is orbiting around an arbitrary planet 'P' at a height of 11R above the surface of 'P', R being the radius of 'P'. The time period of another satellite in hours at a height of 2R from the surface of 'P' is ________...
MCQ+4 / -12021
18Heat And Thermodynamics
If one mole of the polyatomic gas is having two vibrational modes and \(\beta\) is the ratio of molar specific heats for polyatomic gas \(\left( {\beta = {{{C_P}} \over {{C_V}}}} \right)\) then the value of \(\beta\) is :
MCQ+4 / -12021
19Heat And Thermodynamics
Which one is the correct option for the two different thermodynamic processes?
MCQ+4 / -12021
20Laws Of Motion
A body of mass 1 kg rests on a horizontal floor with which it has a coefficient of static friction \({1 \over {\sqrt 3 }}\). It is desired to make the body move by applying the minimum possible force F N. The value of F will be ____________...
INTEGER+4 / -12021
21Laws Of Motion
A boy of mass 4 kg is standing on a piece of wood having mass 5 kg. If the coefficient of friction between the wood and the floor is 0.5, the maximum force that the boy can exert on the rope so that the piece of wood does not move from its ...
INTEGER+4 / -12021
22Magnetics
A hairpin like shape as shown in figure is made by bending a long current carrying wire. What is the magnitude of a magnetic field at point P which lies on the centre of the semicircle?
MCQ+4 / -12021
23Motion In A Straight Line
A rubber ball is released from a height of 5 m above the floor. It bounces back repeatedly, always rising to \({{81} \over {100}}\) of the height through which it falls. Find the average speed of the ball. (Take g = 10 ms\(-\)2)
MCQ+4 / -12021
24Motion In A Straight Line
The velocity of a particle is v = v0 + gt + Ft2. Its position is x = 0 at t = 0; then its displacement after time (t = 1) is :
MCQ+4 / -12021
25Properties Of Matter
An object is located at 2 km beneath the surface of the water. If the fractional compression \({{\Delta V} \over V}\) is 1.36%, the ratio of hydraulic stress to the corresponding hydraulic strain will be ____________. [Given : density of wa...
MCQ+4 / -12021
26Properties Of Matter
Suppose you have taken a dilute solution of oleic acid in such a way that its concentration becomes 0.01 cm3 of oleic acid per cm3 of the solution. Then you make a thin film of this solution (monomolecular thickness) of area 4 cm2 by consid...
INTEGER+4 / -12021
27Rotational Motion
A sphere of mass 2 kg and radius 0.5 m is rolling with an initial speed of 1 ms-1 goes up an inclined plane which makes an angle of 30\(^\circ\) with the horizontal plane, without slipping. How long will the sphere take to return to the sta...
MCQ+4 / -12021
28Simple Harmonic Motion
Two particles A and B of equal masses are suspended from two massless springs of spring constants K1 and K2 respectively. If the maximum velocities during oscillations are equal, the ratio of the amplitude of A and B is
MCQ+4 / -12021
29Simple Harmonic Motion
A block of mass 1 kg attached to a spring is made to oscillate with an initial amplitude of 12 cm. After 2 minutes the amplitude decreases to 6 cm. Determine the value of the damping constant for this motion . (take ln 2 = 0.693)
MCQ+4 / -12021
30Waves
A sound wave of frequency 245 Hz travels with the speed of 300 ms\(-\)1 along the positive x-axis. Each point of the wave moves to and from through a total distance of 6 cm. What will be the mathematical expression of this travelling wave?
MCQ+4 / -12021
