JEE Main 2020 (Online) 5th September Evening Slot

A radioactive nucleus decays by two different
processes. The half life for the first process is
10 s and that for the second is 100 s. The
effective half life of the nucleus is close to :

A parallel plate capacitor has plate of length
'l', width ‘w’ and separation of plates is ‘d’. It
is connected to a battery of emf V. A dielectric
slab of the same thickness ‘d’ and of dielectric
constant k = 4 is being inserted between the...

In the circuit shown, charge on the 5 \(\mu\)F
capacitor is :

A galvanometer is used in laboratory for
detecting the null point in electrical
experiments. If, on passing a current of 6 mA it
produces a deflection of 2o, its figure of merit
is close to :

In the circuit, given in the figure currents in
different branches and value of one resistor are
shown. Then potential at point B with respect to
the point A is :

The surface of a metal is illuminated alternately
with photons of energies E1 = 4 eV and E2 = 2.5 eV
respectively. The ratio of maximum speeds of the
photoelectrons emitted in the two cases is 2. The
work function of the metal in (eV) is __...

An infinitely long, straight wire carrying current
I, one side opened rectangular loop and a
conductor C with a sliding connector are
located in the same plane, as shown, in the
figure. The connector has length \(l\) and
resistance R. It sl...

The correct match between the entries in
column I and column II are :

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Two Zener diodes (A and B) having breakdown
voltages of 6 V and 4 V respectively, are
connected as shown in the circuit below. The
output voltage V0 variation with input voltage
linearly increasing with time, is given by :
(Vinput = 0 V at ...

Ten charges are placed on the circumference
of a circle of radius R with constant angular
separation between successive charges.
Alternate charges 1, 3, 5, 7, 9 have charge (+q)
each, while 2, 4, 6, 8, 10 have charge (–q) each.
The potentia...

A prism of angle A = 1o has a refractive index
\(\mu\) = 1.5. A good estimate for the minimum angle
of deviation (in degrees) is close to \({N \over {10}}\).
Value of N is ____.

The acceleration due to gravity on the earth’s
surface at the poles is g and angular velocity of
the earth about the axis passing through the
pole is \(\omega\). An object is weighed at the equator
and at a height h above the poles by usin...

Two different wires having lengths L1 and L2,
and respective temperature coefficient of linear
expansion \(\alpha\)1 and \(\alpha\)2, are joined end-to-end.
Then the effective temperature coefficient of
linear expansion is :

Nitrogen gas is at 300oC temperature. The
temperature (in K) at which the rms speed of a
H2 molecule would be equal to the rms speed
of a nitrogen molecule, is _______.
(Molar mass of N2 gas 28 g).

In an adiabatic process, the density of a
diatomic gas becomes 32 times its initial value.
The final pressure of the gas is found to be n
times the initial pressure. The value of n is :

A spaceship in space sweeps stationary
interplanetary dust. As a result, its mass
increases at a rate \({{dM\left( t \right)} \over {dt}}\) = bv2(t), where v(t) is
its instantaneous velocity. The instantaneous
acceleration of the satellite ...

An iron rod of volume 10–3 m3 and relative
permeability 1000 is placed as core in a
solenoid with 10 turns/cm. If a current of 0.5 A
is passed through the solenoid, then the
magnetic moment of the rod will be :

The velocity (v) and time (t) graph of a body in
a straight line motion is shown in the figure.
The point S is at 4.333 seconds. The total
distance covered by the body in 6 s is :

In an experiment to verify Stokes law, a small
spherical ball of radius r and density \(\rho\) falls
under gravity through a distance h in air before
entering a tank of water. If the terminal velocity
of the ball inside water is same as it...

A thin rod of mass 0.9 kg and length 1 m is
suspended, at rest, from one end so that it can
freely oscillate in the vertical plane. A particle
of move 0.1 kg moving in a straight line with
velocity 80 m/s hits the rod at its bottom most
poi...

A ring is hung on a nail. It can oscillate, without
slipping or sliding (i) in its plane with a time
period T1 and, (ii) back and forth in a direction
perpendicular to its plane, with a period T2. The
ratio \({{{T_1}} \over {{T_2}}}\) will ...

The quantities x = \({1 \over {\sqrt {{\mu _0}{\varepsilon _0}} }}\), y = \({E \over B}\) and z = \({l \over {CR}}\) are
defined where C-capacitance, R-Resistance,
l-length, E-Electric field, B-magnetic field and
\({{\varepsilon _0}}\), $${...

Two coherent sources of sound, S1 and S2,
produce sound waves of the same wavelength,
\(\lambda\) = 1 m, in phase. S1 and S2 are placed 1.5 m
apart (see fig). A listener, located at L, directly
in front of S2 finds that the intensity is at...

A driver in a car, approaching a vertical wall
notices that the frequency of his car horn, has
changed from 440 Hz to 480 Hz, when it gets
reflected from the wall. If the speed of sound in
air is 345 m/s, then the speed of the car is :

A body of mass 2 kg is driven by an engine
delivering a constant power of 1 J/s. The body
starts from rest and moves in a straight line.
After 9 seconds, the body has moved a
distance (in m) _______.