AIIMS 2018

Assertion In isothermal process, whole of
the heat energy supplied to the body is
converted into internal energy.
Reason According to the first law of
thermodynamics,
\(\Delta Q=\Delta U+\Delta W\)

Assertion Internal energy of an ideal gas
does not depend on volume of gas.
Reason Internal energy depends only on
temperature of gas.

A wooden wedge of mass \(M\) and inclination angle \((\alpha)\) rest on a smooth floor. A block of mass $m$ is kept on wedge. A force \(F\) is applied on the wedge as shown in the figure such that block remains stationary with respect to we...

A piece of ice slides down a rough inclined plane at \(45^{\circ}\) inclination in twice the time that it takes to slide down an identical but frictionless inclined plane. What is the coefficient of friction between ice and incline?

A body of mass 5 kg is suspended by a spring
balance on an inclined plane as shown in
figure.

So, force applied on spring balance is

In the figure, blocks A and B of
masses 2m and m are connected
with a string and system is hanged
vertically with the help of a spring.
Spring has negligible mass. Find
out magnitude of acceleration of
masses 2m and m just after the
instan...

In the figure, mass of a ball is \(\frac{9}{5}\) times mass of the rod. Length of rod is \(1 \mathrm{~m}\). The level of ball is same as rod level. Find out time taken by the ball to reach at upper end of rod.

Assertion Angle of repose is equal to angle
of limiting friction.
Reason When a body is just at the point of
motion, the force of friction of this stage is
called as limiting friction.

The horizontal component of the earth's magnetic field at any place is \(0.36 \times 10^{-4} \mathrm{~Wb} / \mathrm{m}^2\). If the angle of dip at that place is \(60^{\circ}\), then the value of vertical component of the earth's magnetic fi...

Assertion The maximum height of projectile
is always 25% of the maximum range.
Reason For maximum range, projectile
should be projected at 90°.

Assertion A body is momentarily at rest at
the instant, if it reverse the direction.
Reason A body cannot have acceleration, if
its velocity is zero at a given instant of time.

A long straight wire, carrying current \(I\) is bent at its mid-point to form an angle of \(45^{\circ}\). Induction of magnetic field (in tesla) at point \(P\), distant \(R\) from point of bending is equal to

An element \(d l=d x \hat{\mathbf{i}}\) (where, \(d x=1 \mathrm{~cm}\) ) is placed at the origin and carries a large current \(i=10 \mathrm{~A}\). What is the magnetic field on the \(Y\)-axis at a distance of \(0.5 \mathrm{~m}\) ?

Consider the following figure, a uniform
magnetic field of 0.2 T is directed along the
positive X-axis. The magnetic flux through
top surface of the figure.

Assertion A magnetic field interacts with a
moving charge and not with a stationary
charge.
Reason A moving charge produce a
magnetic field.

A block of rectangular size of mass \(m\) and area of cross-section \(A\), floats in a liquid of density \(\rho\). If we give a small vertical displacement from equilibrium, it undergoes SHM with time period \(T\), then

Assertion A pendulum is falling freely its
time period becomes zero.
Reason Freely falling body has the
acceleration equal to g.

Assertion Smaller drop of water resist deformation forces better than the larger drops.
Reason Excess pressure inside drop is inversely proportional to its radius.

A thin horizontal circular disc is rotating about a vertical axis passing through its centre. An insect is at rest at a point near the rim of disc. The insect now moves along a diameter of the disc to reach its other end. During the journey...

Assertion The angular momentum of
system always remain constant.
Reason For a system, \(\tau_{\mathrm{ext}}=\frac{d L}{d t}=0\)

The diode used at a
constant potential drop
of 0.5 V at all currents
and maximum power
rating of 100 mW. What
resistance must be
connected in series diode, so that current in
circuit is maximum?

Assertion Thickness of depletion layer is
fixed in all semiconductor devices.
Reason No free charge carriers are available
in depletion layer.

If the formula, \(X=3 Y Z^2, X\) and \(Z\) have dimensions of capacitance and magnetic induction. The dimensions of \(Y\) in MKSQ system are

An unpolarised beam of intensity \(2 a^2\) passes through a thin polaroid. Assuming zero absorption in the polaroid, the intensity of emergent plane polarised light is

Red light of wavelength 5400 \(\mathop A\limits^o\) from a
distant source falls on a slit 0.80 mm wide.
Calculate the distance between first two dark
bands on each side of central bright band in
the diffraction pattern observed on a screen...

Assertion : If a glass slab is placed in front of
one of the slits, then fringe with will
decrease.
Reason : Glass slab will produce an
additional path difference.

A steel rod 100 cm long is damped at into
middle. The fundamental frequency of
longitudinal vibrations of the rod are given
to be 2.53 kHz. What is the speed of sound
in sound is steel?

A pipe of length 85 cm is closed from one
end. Find the number of possible natural
oscillations of air column in the pipe whose
frequencies lie below 1250 Hz. The velocity
of sound in air is 340 m/s.

Assertion To hear different beats difference
of the frequencies of two sources should be
less than 10.
Reason More the number of beats more in
the confusion.

The figure shows a mass \(m\) on a frictionless surface. It is connected to rigid wall by the mean of a massless spring of its constant \(k\). Initially, the spring is at its natural position. If a force of constant magnitude starts acting ...