Part Test - 10 (JEE Main 2018) - JEE MCQ

C = 8μF capacitor is charged to V₀ = 120 volt. The charging battery is then removed and the capacitor is connected to a series combination of two uncharged capacitor of 4 μF each. The ratio of
final energy stored in 8μF capacitor and each 4μF capacitor is-

The current I and potential difference between X and Y as VXY are:

A particle (q, m) enter a  with velocity v, find derivation path of particle (Magnetic field is in
circular region and its direction is –ve z)

Two identical wires A and B have the same length L and carry the same current I. Wire A is bent into a
circle of radius R and wire B is bent to form a square of side a. If B1 and B2 are the values of magnetic
induction at the centre of the circle and the centre of the square respectively, then the ratio of B1/B2 is:

An electron is confined to a tube of length L. The electron’s potential energy in one half of the tube is zero, while the potential energy in the other half is 10 eV. If the electron has a total energy E =15 eV, then the ratio of the de-Broglie wavelength of the electron in the 10 eV region of the tube to that in the other half is -

The cathode of a photoelectric cell is changed such that the work function changes from W₁ to W₂
(W₂ > W₁). If the current before and after changes are I₁ and I₂ all other conditions remaining
unchanged, then (assuming hv > W₂) -

The current through an ideal PN junction shown in the following circuit diagram will be -

In YDSE experiment, intensity at some point on central fringe is 1/4th of the maximum intensity
then angular position of this point is (d : separation between the slits & λ is the wavelength of light)

A plastic disc of radius R has a charge q uniformly distributed over its surface. If the disc is rotated
with a frequency f about its axis, then the magnetic induction at the centre of the disc is given by:

Two stretched membranes of areas 2 and 3 m² are placed in a liquid at the same depth. The ratio of the pressure on them is -

A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is 4/3 and the fish is 12 cm below the surface, the radius of this circle in cm is-

A body cools in surrounds of temperature θ₀. It’s temperature is plotted against t. Tangent drawn
at point P & Q then-

Under the action of a force a 2kg mass moves such that its position x as a function of time is given by
x = t³/3 where x is in metres and t in seconds. The work done by the force in first two seconds is-

A and B are two points on a uniform metal ring of centre C. The angle ACB = θ. A and B are maintained at two different constant temperature. When θ = 180º, the rate of total heat flow from A to B is 1.2 W. When θ = 90ºC this rate will be-

An electron is moving in a circular orbit of radius R with an angular acceleration α. At the centre of the orbit is kept a conducting loop of radius r, (r << R). The e.m.f., induced in the smaller loop due to the motion of the electron is -

When temperature of a body increases from t to t + Δt, its moment of inertia increases from I to I+ ΔI. Coefficient of linear expansion of the body is α, then ΔI/I  is equal to-

Tow smooth cylindrical bars weighing W N each lie next to each other in contact. A similar third bar is placed over the two bars as shown in figure. Neglecting friction, the horizontal force on each lower bar necessary to keep them together is

A uniform rod of length L and mass M lies on a frictionless table is free to move on the table. A particle of mass m moving with velocity u collides elastically with the rod at a distance L/3 from its centre and comes to
rest immediately after collision. The ratio M/m is 

Two blocks each of mass m are connected to a spring of spring constant k. If both are given velocity v in opposite directions, then the maximum elongation of the spring is :

The moment of inertia of a uniform rod of mass M and length L about an axis through centre and
perpendicular to length L is given by ML²/12. Now, consider one such rod pivoted at its centre free
to rotate in a vertical plane. The rod is at rest in the vertical position. A bullet of mass M moving
horizontally at a speed u strikes and gets embedded in one end of the rod. The angular velocity ω
of the rod after collision will be :

A body travelling along a straight line traversed one-third of the total distance with a velocity v₁. The
remaining part of the distance was covered with a velocity v₂ for half the time and with velocity v₃ for
the other half of time. The mean velocity averaged over the whole time of motion is :

Let g be acceleration due to gravity on the surface of the earth and K_R be the rotational kinetic energy
of the earth. Suppose the earth’s radius decreases by 2%, keeping all other quantities same (even ω) :

Three particles A, B and C are thrown from the top of a tower with the same speed. A is thrown up,
B is thrown down and C is thrown horizontally. They hit the ground with speeds v_A, v_B and v_C
respectively :
 

The potential energy of a particle of mass m is given by U(x) = 
λ₁ and λ₂ are the de-Broglie wavelength of the particle, when 0  x  1 and x > 1 respectively if the
total energy of the particle is 2E₀ the ratio of λ₁ /λ₂ will be -

The de-broglie wavelength of the electron in the second Bohr orbit is (given the radius of the first
orbit r₁ = 0.53 Å)

Reading of the spring scale in figure is, if lift is moving vertically
upward with acceleration g/2

The masses and the radii of earth and moon are respectively M_e, R_e and M_m, R_m. The distance between
the centres is r. At what minimum velocity a particle of mass m be projected from the mid point of the
distance between their centres so that it may escape into space ?