Indian Institute of Information Technology 2006 Entrance Exams IIT Entrance Exams IIT Study circle  Physics aptitude Test  Question Paper
Tuesday, 22 January 2013 11:30Web
IIT Study circle  Physics aptitude Test
PHYSICS
PHYSICS
Time: ONE Hour

Max. Marks: 60

 Answers
must be written either in English or the medium of instruction of the
candidate in high school.
 Answer
all the questions in the booklets provided for the purpose.
 There
will be no negative marking.
 The
relevant working in arriving at an answer has to be shown wherever
required. However if the answer can be arrived at without detailed
working, write only the answer
 Use
of calculators or graph papers is not permitted.
 Questions
in part A carry 5 marks each and those in part B carry 2 marks each
Some useful data:
Density
of water = 1 g cm^{3}
Specific
heat of water = 4.2 J g^{1}K^{1}=1 cal/g C^{o}
Density
of Ice = 0.9 gm/cm^{3}
Latent
Heat of Ice = 80 cal/g
PART A
 On a long journey if 10% of the distance is
covered at an average speed of 40 km/h and 90% of the distance is
covered at an average speed of 90 km/h. What is the average speed
for the entire journey? How does this answer change if the percentages
relate to time rather than distance, that is, if 10% of the duration is
covered at 40 km/h and 90% of the duration is covered at average
speed of 90 km/h.
 In two
glasses there is liquid material of the same type, the volume of one is V_{1},
its temperature of is T_{1}, the volume of the other is V_{2}
and its temperature is T_{2}. We mix the liquids and wait
while the temperature settles. What is the common temperature if we
neglect any heat losses? What would be the common temperature if the
volume of first liquid is halved and the second liquid doubled.
 Three ice cubes each of side 2 cm at 0
C are dropped into a glass of 18 C water. The volume of the
water is 200 cm^{3}. What are the volume and the temperature of
the water after the ice cubes have melted?
 How much can the temperature of the water in a
50 m x 25 m x 2 m size pool be raised with
the energy released by a single gram of 235 Uranium isotope in a nuclear
power plant? Assume 47% of the energy (200 MeV of energy is
liberated in the fission of one isotope) is used to heat up the water.
 Two
cars are 60 km away from each other and are moving towards each
other at 116 km/h and 184 km/h. How far are they from each
other one and a half minutes before their collision?
 A ray
of light is incident on an isosceles rightangled prism made of a
material of critical angle 42 . Find the distance of
point of emergence of the ray from the prism if AB = d and AP = L


 Large
number of identical blocks are placed on a surface with adjacent
blocks d apart. The left most block is imparted a velocity V to the
right. On striking its neighbour it comes to rest and the struck block
takes off at 0.8 V. This process repeats. What is the time
interval between the third and fourth hits? Assume that the motion
between the hits is uniform. Neglect the duration of collision.


 A
stick of height h is protruding out of a liquid contained in a large
vessel with half of it inside the liquid. Rays of light from after noon sun are incident on the stick at 45 as shown by the dotted
lines. Find the length of the shadow on the bottom of the vessel.
Would the shadow length increase or decrease as the sun goes down
further?


 The
wire mesh shown is made of a uniform wire. Resistance between any two
points is R. When wires OH and OD are removed some current flows
between the terminals when a potential difference V is applied between
them. If now the wires OB and OF are also removed, find the change in
potential difference for same current to flow between the terminals.


 Ratio
of specific heats g of a mixture of gases is
given by where C_{v1}
and C_{v2} are the specific heats at constant volume of the two
gases in the mixture and g is the ratio of specific
heats, n_{1} and n_{2} are the number of moles of the
gas in the given mixture.
Find
the velocity of sound in a mixture by equal volumes Hydrogen and Helium at 27
C. Specific heats at constant volume for Hydrogen and Helium are 5R/2 and
3R/2 respectively.
PART B
11.
Two pendulums are
drawn aside and released at the same time. One has a time period of 2 s
and the other 2.5 s. What is the least time when they are at their
extreme positions on opposite sides of equilibrium?
 At a given time, the distance recorder of a car
cruising at near constant speed on a road showed 24, 942 km. Two
hours later the driver noticed that it showed a symmetric number again.
What was the average speed of the car in this twohour leg?
 Explain why a glass of water quickly warms up
when placed on a hot surface but does not cool as quickly when placed on
a cold surface. Assume same temperature differences between the water
and the surfaces in both the cases.
 Two resistances, a 60 ohm and an unknown
one are connected to a power source of 120 V in a series arrangement.
This way the power of the unknown resistance is 60 W. What is the
Unknown resistance?
 A
hollow sphere made of material of density 3 g/cm^{3} is floating
with three fourth of its volume submerged in a liquid of density 0.8
g/cm^{3}. If the external volume of the sphere is 200 cm^{3},
find the volume of the cavity inside the sphere.

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