NEET 2018

The magnetic potential energy stored in a
certain inductor is 25 mJ, when the current
in the inductor is 60 mA. This inductor is of
inductance

An inductor 20 mH, a capacitor 100 \(\mu\)F and
a resistor 50 \(\Omega\) are connected in series across
a source of emf, V = 10 sin 314 t. The power
loss in the circuit is

The ratio of kinetic energy to the total energy
of an electron in a Bohr orbit of the hydrogen
atom, is

For a radioactive material, half-life is 10
minutes. If initially there are 600 number of
nuclei, the time taken (in minutes) for the
disintegration of 450 nuclei is

The electrostatic force between the metal plates
of an isolated parallel plate capacitor C having
a charge Q and area A, is

A moving block having mass m, collides with
another stationary block having mass 4m. The
lighter block comes to rest after collision. When
the initial velocity of the lighter block is v, then
the value of coefficient of restitution (e) will...

A set of n equal resistors, of value R each, are
connected in series to a battery of emf E and
internal resistance R. The current drawn is I. Now,
the n resistors are connected in parallel to the
same battery. Then the current drawn from ba...

A battery consists of a variable number n of
identical cells (having internal resistance r each)
which are connected in series. The terminals
of the battery are short-circuited and the current
I is measured. Which of the graphs shows the
co...

A carbon resistor of (47 \(\pm\) 4.7) k\(\Omega\) is to be marked
with rings of different colours for its identification.
The colour code sequence will be

When the light of frequency 2\({\upsilon _0}\)
(where \({\upsilon _0}\)
is
threshold frequency), is incident on a metal
plate, the maximum velocity of electrons
emitted is v1
. When the frequency of the
incident radiation is increased to ...

An electron of mass m with an initial velocity
\(\overrightarrow v = {v_0}\widehat i\) (v0 > 0)
enters an electric field
\(\overrightarrow E = - {\overrightarrow E _0}\widehat i\)
(E0
= constant > 0) at t = 0. If \(\lambda\)0
is its ...

An EM wave is propagating in a medium with
a velocity \(\overrightarrow v = v\widehat i\). The instantaneous
oscillating electric field of this em wave is
along +y axis. Then the direction of oscillating
magnetic field of the em wave will ...

A toy car with charge q moves on a frictionless
horizontal plane surface under the influence of
a uniform electric field \(\overrightarrow E\)
. Due to the force q\(\overrightarrow E\)
,
its velocity increases from 0 to 6 m s–1 in one
sec...

An electron falls from rest through a vertical
distance h in a uniform and vertically upward
directed electric field E. The direction of electric
field is now reversed, keeping its magnitude the
same. A proton is allowed to fall from rest i...

The refractive index of the material of a prism
is \(\sqrt 2\) and the angle of the prism is 30°. One
of the two refracting surfaces of the prism is
made a mirror inwards, by silver coating. A
beam of monochromatic light entering the
prism...

An astronomical refracting telescope will have
large angular magnification and high angular
resolution, when it has an objective lens of

An object is placed at a distance of 40 cm
from a concave mirror of focal length 15 cm.
If the object is displaced through a distance
of 20 cm towards the mirror, the displacement
of the image will be

The kinetic energies of
a planet in an elliptical
orbit about the Sun, at
positions A, B and C are
KA, KB and KC, respectively. AC is the major
axis and SB is perpendicular to AC at the position
of the Sun S as shown in the figure. Then

If the mass of the Sun were ten times smaller
and the universal gravitational constant were
ten times larger in magnitude, which of the
following is not correct?

The volume (V) of a monatomic
gas varies with its temperature
(T), as shown in the graph. The
ratio of work done by the gas,
to the heat absorbed by it, when
it undergoes a change from state
A to state B, is

A sample of 0.1 g of water at 100°C and normal
pressure (1.013 × 105
N m–2) requires 54 cal
of heat energy to convert to steam at 100°C.
If the volume of the steam produced is 167.1 cc,
the change in internal energy of the sample, is

At what temperature will the rms speed of
oxygen molecules become just sufficient for
escaping from the Earth’s atmosphere? (Given :
Mass of oxygen molecule (m) = 2.76 × 10–26 kg,
Boltzmann’s constant kB
= 1.38 × 10–23 J K–1)

The efficiency of an ideal heat engine working
between the freezing point and boiling point
of water, is

Which one of the following statements is
incorrect?

A block of mass m is placed on a smooth inclined
wedge ABC of inclination q as shown in the
figure. The wedge is given an acceleration ‘a’
towards the right. The relation between a and q
for the block to remain stationary on the wedge
is

A thin diamagnetic rod is placed vertically
between the poles of an electromagnet. When
the current in the electromagnet is switched
on, then the diamagnetic rod is pushed up, out
of the horizontal magnetic field. Hence the rod
gains gravit...

Current sensitivity of a moving coil
galvanometer is 5 div/mA and its voltage
sensitivity (angular deflection per unit voltage
applied) is 20 div/V. The resistance of the
galvanometer is

A metallic rod of mass per unit length
0.5 kg m–1 is lying horizontally on a smooth
inclined plane which makes an angle of 30° with
the horizontal. The rod is not allowed to slide
down by flowing a current through it when a
magnetic field o...

A pendulum is hung from the roof of a
sufficiently high building and is moving freely
to and fro like a simple harmonic oscillator.
The acceleration of the bob of the pendulum
is 20 m s–2 at a distance of 5 m from the mean
position. The tim...

The power radiated by a black body is P and it
radiates maximum energy at wavelength, \(\lambda\)0
. If
the temperature of the black body is now
changed so that it radiates maximum energy at
wavelength \({3 \over 4}{\lambda _0}\), the powe...

A small sphere of radius ‘r’ falls from rest in a
viscous liquid. As a result, heat is produced
due to viscous force. The rate of production of
heat when the sphere attains its terminal velocity,
is proportional to

Two wires are made of the same material and
have the same volume. The first wire has
cross-sectional area A and the second wire has
cross-sectional area 3A. If the length of the first
wire is increased by \(\Delta\)l on applying a force F,...

A solid sphere is in rolling motion. In rolling
motion a body possesses translational kinetic
energy (Kt) as well as rotational kinetic energy
(Kr) simultaneously. The ratio Kt
: (Kt + Kr)
for the sphere is

Three objects, A : (a solid sphere), B : (a thin
circular disk) and C : (a circular ring), each
have the same mass M and radius R. They
all spin with the same angular speed \(\omega\) about
their own symmetry axes. The amounts of
work (W) ...

The moment of the force, \(\overrightarrow F = 4\widehat i + 5\widehat j - 6\widehat k\) at
(2, 0, –3), about the point (2, –2, –2), is given by

A solid sphere is rotating freely about its
symmetry axis in free space. The radius of
the sphere is increased keeping its mass same.
Which of the following physical quantities
would remain constant for the sphere?

In a p-n junction diode, change in temperature
due to heating

In the circuit shown in the figure, the input
voltage Vi
is 20 V, VBE = 0 and VCE = 0. The
values of IB
, IC
and \(\beta\) are given by

In the combination of the following gates
the output Y can be written in terms of inputs
A and B as

A student measured the diameter of a small
steel ball using a screw gauge of least count
0.001 cm. The main scale reading is 5 mm and
zero of circular scale division coincides with
25 divisions above the reference level. If screw
gauge has ...

In Young’s double slit experiment the
separation d between the slits is 2 mm, the
wavelength \(\lambda\) of the light used is 5896 \(\mathop A\limits^0\) and
distance D between the screen and slits is
100 cm. It is found that the angular ...

Unpolarised light is incident from air on a
plane surface of a material of refractive index
\(\mu\). At a particular angle of incidence i, it is
found that the reflected and refracted rays
are perpendicular to each other. Which of
the foll...

The fundamental frequency in an open organ
pipe is equal to the third harmonic of a closed
organ pipe. If the length of the closed organ
pipe is 20 cm, the length of the open organ
pipe is

A tuning fork is used to produce resonance in
a glass tube. The length of the air column in
this tube can be adjusted by a variable piston.
At room temperature of 27°C two successive
resonances are produced at 20 cm and 73 cm
of column leng...

A body initially at rest
and sliding along a
frictionless track from
a height h (as shown
in the figure)
just completes a vertical circle of diameter
AB = D. The height h is equal to