JEE Main 2021 July 20 Shift 2 Question Paper & Solutions - JEE MCQ

At an angle of 30° to the magnetic meridian, the apparent dip is 45°. Find the true dip.

A body rolls down an inclined plane without slipping. The kinetic energy of rotation is 50% of its translational kinetic energy. The body is:

Consider a binary star system of star A and star B with masses m_A and m_B revolving in a circular orbit of radii r_A and r_B, respectively. If T_A and T_B are the time periods of star A and star B, respectively, then

A satellite is launched into a circular orbit of radius R around earth, while a second satellite is launched into a circular orbit of radius 1.02R. The percentage difference in the time periods of the two satellites is:

For a certain radioactive process, the graph between ln R and t (sec) is obtained as shown in the figure. Then the value of half life for the unknown radioactive material is approximately:

A boy reaches the airport and finds that the escalator is not working. He walks up the stationary escalator in time t₁. If he remains stationary on a moving escalator, then the escalator takes him up in time t₂. The time taken by him to walk up on the moving escalator will be:

A particle is making simple harmonic motion along the x-axis. At distances x₁ and x₂ from the mean position, the velocities of the particle are v₁ and v₂, respectively. The time period of its oscillation is given as:
 

The magnetic susceptibility of a material of a rod is 499. Permeability in vacuum is 4π × 10^-7 H/m. Absolute permeability of the material of the rod is

With what speed should a galaxy move outward with respect to earth so that the sodium-D line at wavelength 5890 Å is observed at 5896 Å?

If time (t), velocity (v), and angular momentum (l) are taken as the fundamental units, then the dimension of mass (m) in terms of t, v and I is

Two small drops of mercury each of radius R coalesce to form a single large drop. The ratio of total surface energy before and after the change is:

Two vectors  have equal magnitudes. If the magnitude of   is n times the magnitude of  then angle between  is: 

The correct relation between the degree of freedom f and the ratio of specific heat γ is:

The length of a metal wire is l₁, when the tension in it is T₁ and is l₂ when the tension is T₂. The natural length of the wire is:

If the kinetic energy of a moving body becomes four times its initial kinetic energy, then the percentage change in its momentum will be:

In an electromagnetic wave, the electric field vector and magnetic field vector are given as respectively. The direction of propagation of electromagnetic wave is along

Which of the following graphs represent the behaviour of an ideal gas?
Symbols have their usual meaning

A radioactive substance decays to (1/16)th of its initial activity in 80 days. The half life of the radioactive substance expressed in days is _____.

A series LCR circuit of R = 5Ω, L = 20 mH and C = 0.5μF is connected across an AC supply of 250 V, having variable frequency. The power dissipated at resonance condition is _________ × 10² W.

A zener diode having zener voltage 8 V and power dissipation rating of 0.5 W is connected across a potential divide arranged with maximum potential drop across zener diode is as shown in the diagram. The value of protective resistance R_p is ___________ Ω.

One mole of an ideal gas at 27°C is taken from A to B as shown in the given PV indicator diagram. The work done by the system will be ___________ × 10^-1 J.
[Given: R = 8.3 J/mole K, In 2 = 0.6931] (Round off to the nearest integer)

For the forward biased diode characteristics shown in the figure, the dynamic resistance at ID = 3 mA will be _________ Ω.

Two bodies, a ring and a solid cylinder of same material are rolling down without slipping an inclined plane. The radii of the bodies are same. The ratio of velocity of the centre of mass at the bottom of the inclined plane of the ring to that of the cylinder is √x/2. Then the value of x is _______.

In the given figure, switches S₁ and S₂ are in open condition. The resistance across ab when the switches S₁ and S₂ are closed is _________ Ω.

A body of mass 'm' is launched up on a rough inclined plane making an angle of 30° with the horizontal. The coefficient of friction between the body and plane is √x/5 if the time of ascent is half of the time of descent. The value of x is _______.

A body rotating with an angular speed of 600 rpm is uniformly accelerated to 1800 rpm in 10 sec. The number of rotations made in the process is _______.

A certain metallic surface is illuminated by monochromatic radiation of wavelength λ. The stopping potential for photoelectric current for this radiation is 3V₀. If the same surface is illuminated with a radiation of wavelength 2λ, the stopping potential is V₀. The threshold wavelength of this surface for photoelectric effect is ________ λ.