JEE Main 2019 April 8 Shift 2 Paper & Solutions - JEE MCQ

In a line of sight radio communication, a distance of about 50 km is kept betweenthe transmitting and receiving antennas. If the height of the receiving antenna is 70m, then the minimum height of the transmitting antenna should be:(Radius of the Earth = 6.4*10⁶ m)

In a simple pendulum experiment for determination of acceleration due to gravity(g), time taken for 20 oscillations is measured by using a watch of 1 second leastcount. The mean value of time taken comes out to be 30 s. The length of pendulum ismeasured by using a meter scale of least count 1 mm and the value obtained is55.0 cm. The percentage error in the determination of g is close to:

A parallel plate capacitor has 1μF capacitance. One of its two plates is given +2μCcharge and the other plate, +4μC charge. The potential difference developed acrossthe capacitor is:

Two magnetic dipoles X and Y are placed at a separation d, with their axes perpendicular to each ot.her. The dipole moment 0f Y is twice that of X. A particle of charge q is passing through their mid–point P, at angle θ = 45° with the
horizontal line, as shown in figure. What would be the magnitude of force on the particleat that instant ? (d is much larger than the dimensions of the dipole)

A solid sphere and solid cylinder of identical radii approach an incline with the same linear velocity (see figure). Both roll without slipping all throughout. The two climb maximum heights h_sph and h_cyl on the incline. The ratio  
 is given by:

A nucleus A, with a finite de–broglie wavelength λ_A, undergoes spontaneous fission into two nuclei B and C of equal mass. B flies in the same direction as that of A, while C flies in the opposite direction with a velocity equal to half of that of B. The de–Broglie wavelengths λ_B and λ_C of B and C are respectively :

The temperature, at which the root mean square velocity of hydrogen molecules equals their escape velocity from the earth, is closest to:
[Boltzmann Constant kB =1.38 X 10–23 J/K Avogadro Number NA = 6.02 X 1026 /kg Radius of Earth : 6.4 X 106 m
Gravitational acceleration on Earth = 10 ms–2]

A circuit connected to an ac source of emf e=e₀ sin(100t) with t in seconds, gives aphase difference of π/4 between the emf e and current i. Which of the followingcircuits will exhibit this?

Young’s moduli of two wires A and B are in the ratio 7:4. Wire A is 2m long and hasradius R. Wire B is 1.5 m long and has radius 2 mm. If the two wires stretch by thesame length for a given load, then the value of R is close to :

A body of mass m1 moving with an unknown velocity of , undergoes a collinearcollision with a body of mass m2 moving with a velocity . After collision, m1 andm2 move with velocities of and , respectively. If m₂=0.5 m₁ and v₃ =0.5 v_1​ ,then v₁ is:

A particle starts from origin O from rest and moves with a uniform acceleration along the positive x– axis. Identify the figure that incorrectly represent the motion qualitatively. (a = acceleration, = velocity, x = displacement, t = time)

A positive point charge is released from rest at a distance ro from a positive line charge with uniform density. The speed of the point charge, as a function of instantaneous distance r from line charge, is proportional to:

The electric field in a region is given by , where E is in NC^–1 and x is in metres. The values of constants are A=20 SI unit and B=10 SI unit. If the potential at x=1 isV₁ and that at x= –5 is V₂, then V₁ –V₂is:

The ratio of mass densities of nuclei of ⁴⁰Ca and ¹⁶O is close to:

Two very long, straight, and insulated wires are kept at 90° angle from each other in xy–plane as shown in the figure.

These wires carry currents of equal magnitude I, whose directions are shown in the figure. The net magnetic field at point P will be:

A common emitter amplifier circuit, built using an npn transistor, is shown in the figure. Its dc current gain is 250, R_{C  =}1KΩ and VCC = 10V. What is the minimum base current for V_CE to reach saturation?

If Surface tension (S), Moment of Inertia (I) and Planck's constant (h), were to betaken as the fundamental units, the dimensional formula for Linear momentumwould be:

An electric dipole is formed by two equal and opposite charges q with separation d.The charges have same mass m. It is kept in a uniform electric field E. If it is slightly rotated from its equilibrium orientation, then its angular frequency ω is:

A rocket has to be launched from earth in such a way that it never returns. If E is the minimum energy delivered by the rocket launcher, what should be the mjnimum energy that the launcher should have if the same rocket is to be launched from the surface of the moon ? Assume that the density of the earth and the moon are equal and that the earth's volume is 64 times the volume of the moon.

A convex lens (of focal length 20 cm) and a concave mirror, having their principalaxes along the same lines, are kept 80 cm apart from each other. The concavemirror is to the right of the convex lens. When an object is kept at a distance of 30cm to the left of the convex lens, its image remains at the same position even if theconcave mirror is removed. The maximum distance of the object for which thisconcave mirror, by itself would produce a virtual image would be

In the circuit shown, a four–wire potentiometer is made of a 400 cm long wire,which extends between A and B. The resistance per unit length of the potentiometer wire is r= 0.01 Ω/cm If an ideal voltmeter is connected as shown with jockey J at 50 cm from end A, the expected reading of the voltmeter will be:

A rectangular solid box of length 0.3 m is held horizontally, with one of its sides on the edge of a platform of height 5 m. When released, it slips off the table in a very short time τ =0.01 s, remaining essentially horizontal. The angle by which it would rotate when it hits the ground will be (in radians) close to

Calculate the limit of resolution of a telescope objective having a diameter of 200cm,if it has to detect Light of wavelmgth 500 nm coming from a star.

In the figure shown, what is the current (in Ampere) drawn from the battery? You are given:

The magnetic field of an electromagnetic wave is given by:

The associated electric field will be:

The given diagram shows four processes i.e., isochoric, isobaric, isothermal and adiabatic. The correct assignment of the processes, in the same order is given by: