1. technology and computing
2. computer certification

IITJEE PHYSICS SAMPLE PAPER - III
SECTION – I
Straight Objective Type
This section contains 8 multiple choice questions numbered 1 to 8. Each question has
4 choices (a), (b), (c) and (d), out of which ONLY ONE choice is correct.
1.
1
In the circuit shown in figure, the switch is
shifted from position 1
2 at t = 0. The switch
was initially in position 1 since a long time. The
graph between charge on upper plate of
capacitor versus time t is
2
C
R
2R
2
q
q
2C
2C
(b)
C
t
t
(a)
–C
q
q
3C
2C
(c)
C
t
(d)
t
–C
2.
In Young’s double slit experiment, the introduction of a thin transparent film reduces the
intensity at centre of screen by 75%. Then ( = refractive index of film, t = thickness of film
and =wavelength of light used)
5
5
2t
t
(a)
if
(b)
if
3
2
Space for rough work
5
4
3t
if
(d)
for any value of
3
3
In Coolidge tube experiment, if applied voltage is increased to three times, the short
wavelength limit of continuous X-ray spectrum shifts by 20 pm. What is the initial voltage
applied to the tube?
(a) 20 kV
(b) 41 kV
(c) 52 kV
(d) 102 kV
(c)
3.
4.
A particle is executing simple harmonic motion of amplitude A. At a distance x from the
centre, particle receives a blow in the direction of motion which instantaneously doubles the
velocity. Its new amplitude will be
(a) A
(b)
A2
x2
(c)
2 A2
3x 2
(d)
4 A2
3x 2
5.
Two particles are moving towards each other along a line joining them so that their centre
of mass does not move. After elastic collision between them,
(a) their centre of mass will move
(b) their velocities will not change
(c) their speeds will not change
(d) their velocities will not change if they have equal mass
6.
A long solenoid with 10 turns/cm and a radius of 7 cm carries a current of
20
mA. A
current i exists in a straight conductor located along central axis of the solenoid. What is the
net magnetic field at a point inside the solenoid where it makes an angle 450 with axial
direction?
(a) 8 T
(b) 11.3 T
(c) 11.3 10–3 T
(d) 8 10–3 T
7.
In the circuit shown in figure, if the ideal
ammeter and the ideal source of emf is
physically interchanged then reading of
ammeter will
Space for rough work
5V
4
2
A
6
8.
(a) decrease by two times
(b) increase by two times
(c) increase by 50%
(d) not change
There are two concentric and coplanar nonconducting rings of radii R and 4R. The charge is
distributed uniformly on both rings. The charge on smaller ring is q and charge on larger
ring is –8q. A particle of mass 10 g and charge –q is projected along the axis from infinity.
What is the minimum speed of charge at infinity to reach the common centre of rings
Kq 2 2 5
J)
(take
R
3
(a) 5 m/s
(b) 10 m/s
(c) 20 m/s
(d) 30 m/s
SECTION II
Reasoning Type
This section contains 4 reasoning type questions numbered 9 to 12. Each question contains
Statement-1 and Statement-2. Each question has 4 choices (a), (b), (c) and (d), out of which
ONLY ONE is correct.
Directions: Read the following questions and choose
(A) If both the statements are true and statement-2 is the correct explanation of
statement-1.
(B) If both the statements are true but statement-2 is not the correct explanation of
statement-1.
(C) If statement-1 is True and statement-2 is False.
(D) If statement-1 is False and statement-2 is True.
9.
Statement-1: A solid cylinder is floating in water kept in a container. If container is
moving upward with constant acceleration then length of cylinder inside the water at
equilibrium is greater.
Statement-2: The pressure at a point inside a liquid kept in a container will increase if
container start moving upward with constant acceleration.
(a) A
(b) B
(c) C
(d) D
10.
Statement-1: For a system of particles in conservative field, change in kinetic energy is
same for any inertial reference frame.
Space for rough work
11.
12.
Statement-2: For a system of particles in conservative field, change in potential energy is
same for any inertial reference frame.
(a) A
(b) B
(c) C
(d) D
Statement-1: The frictional drag exerted on a satellite by the atmosphere results in an
increase in speed of satellite.
Statement-2: The line joining the sun to a planet sweeps out equal areas in equal times.
(a) A
(b) B
(c) C
(d) D
Statement-1: If magnetic field in cylindrical
region as shown in figure changes with time then
induced electric field can not be radially outward.
Statement-2: The work done in electric field, produced by time varying magnetic field,
depends on path.
(a) A
(b) B
(c) C
(d) D
SECTION III
Linked Comprehension Type
This section contains 2 paragraphs P13 P18. Based upon each paragraph, 4 multiple choice
questions have to be answered. Each question has 4 choices (a), (b), (c) and (d), out of which
ONLY ONE choice is correct.
Passage-I
A uniform rod of mass M rotates uniformly in alternating directions
to and fro about a horizontal axis passing through its centre, while a
ball of mass m bounces between the ends of rod in vertical plane as
2
shown in figure. The angular speed of the rod is
rad/s and time
3
period of periodic motion of the ball is 2s. (The mechanical loss and
the duration of collision is negligible and g = 10m/s2)
13.
120°
What is the velocity of the ball at the highest point of its path?
(a) 10 m/s
Space for rough work
(b) 5 3 m/s
(c) 5 m/s
(d) 5 2 m/s
14.
What is length of rod?
(b) 10 3 m
(a) 5 3 m
15.
What is the value of
(a)
(d) 5 2 m
m
?
M
(b)
18
(c) 10 m
3
18
(c)
3
18
(d)
3
9
Passage-II
A thermally insulated cylindrical vessel of radius r is
closed with a piston of mass m encloses ideal gas as shown.
The piston can move in the cylinder without friction. At
equilibrium the pressure and volume of the enclosed gas
are P0 and V0 respectively. A small displacement from this
equilibrium position will cause oscillation of the piston
with frequency f.
16.
Determine the frequency of oscillation if the process is isothermal
1
(a)
2
17.
P0 r 2
mV0
2
(b)
1
P0 r 2
mV0
2
Find the value of adiabatic constant
small oscillation)
(a)
18.
m
4 f 2 mV0
P0 r 4
(b)
3 f 2 mV0
P0 r 4
1
(c)
4
P0 r 2
mV0
2
(d) none of these
assuming process to be adiabatic (f is frequency of
(c)
8 f 2 mV0
P0 r 4
(d) none
What is the ratio of time period for adiabatic and isothermal process if is the adiabatic
constant for the gas?
1
(a)
(b)
(c)
(d) none
Space for rough work
SECTION IV
Matrix Match Type
This section contains 2 questions. Each question contains statements given in two columns
which have to be matched. Statements (A), (B), (C), (D) in Column I have to be matched
with statements (1, 2, 3, 4) in Column II. One statement in first column has one or more than
one match with the statements in second column. The answers to these questions have to be
appropriately bubbled as illustrated in the following example.
If the correct matches are A 1,3, B 3, C 2,3 and D 2,4, then the correctly bubbled
4 × 4 matrix should be as follows:
1 2 3 4
A
B
C
D
1.
1
2
3
1
2
3
4
4
1
2
3
4
1
2
3
4
In Young’s double slit experiment, wavelength of light = 6000 Å, screen distance, D = 1m
and slit separation, d = 0.50 mm. Intensity of light through two slits are I0 and 4I0. Column I
indicates the distance of certain point P on screen from central maxima.
Column I
Column II
(A)
y = 2 mm
1.
Intensity at P is 7I0
(B)
y = 2.2 mm
2.
Intensity at P is 3I0
(C)
y = 2.6 mm
3.
P lies between 2nd minima and 2nd
maxima
4.
P lies between 3rd minima and 2nd
maxima
(D)
y = 2.8 mm
Space for rough work
2.
Consider the graph between average
power (P) consumed and angular
frequency ( ) for a series LCR circuit
containing ac source.
P
Pm
Pm /2
1
Column –I
0
2
Column –II
(A) R is increased
1.
Pm remains constant
(B) L is increased
2.
Pm will decreases
(C) C is increased
3.
2
–
(D) L is decreased
4.
0
will decrease
Space for rough work
1
will increase
SECTION V
Subjective or Numerical Type
The answer to these questions would lie between
0 to 9999. For any answer all four bubbles must be
filled, for example if you plan to answer as 16 then fill
0016 and if you plan to answer 0 then fill 0000 in the
grid provided in answer sheet. Any incomplete filling
will be considered as incorrect filling.
Illustration: If you want to fill 2379 as your answer
then it will be filled as
1.
If hydrogen were monoatomic, what temperature would the average translational kinetic
energy be equal to the energy required to raise a hydrogen atom from the ground state to the
n = 2 excited state? (Rhc = 14 eV, k = 1 10 –23 J/K) k is Boltzmann’s constant. The answer
is x 103K. Find x
2.
The diameter of aperture of a plano convex lens is 2 cm and its maximum thickness is
2 mm. If the velocity of light in the material of lens is 2 108 m/s. calculate the focal length
of the lens, in cm.
Space for rough work