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CBSE Questions for Class 11 Engineering Physics Thermal Properties Of Matter Quiz 12 - MCQExams.com

One likes to sit under sunshine in the winter season, because
  • The air surrounding the body is hot by which body gets heat
  • We get energy by the sun
  • We get heat by conduction by sun
  • None of the above
Two rods of the same length and cross-section are joined along the length. Thermal conductivities of the first and second rod are K1 and K2. The temperature of the free ends of the first and second rods are maintained at θ1 and θ2 respectively. The temperature of the common junction is :
  • θ1+θ22
  • K1K2K1+K2(θ1+θ2)
  • K1θ1+K2θ2K1+K2
  • K2θ1+K1θ2K1+K2
Two cylinders P and Q have the same length and diameter and are made of different materials having thermal conductivities in the ratio 2:3. These two cylinders are combined to make a cylinder. One end of P is kept at 100C and another end of Q at 0C. The temperature at the interface of P and Q is 
  • 30C
  • 40C
  • 50C
  • 60C
A thermos flask is polished well
  • To make attractive
  • For shining
  • To absorb all radiations from outside
  • To reflect all radiations from outside
Three rods of the same dimension have thermal conductivities 3K,2K3K,2K. The temperature of their junction is 
1815566_4a392daab6d14f038a459e3b9980a125.jpg
  • 60C
  • 70C
  • 50C
  • 35C
The layers of the atmosphere are heated through 
  • Convection
  • Conduction
  • Radiation
  • (b) and (c) both
A body of length 1m having a cross-sectional area 0.75m2 has heat flow through it at the rate of 6000 Joule/sec. Then find the temperature difference if K=200Jm1K1
  • 20C
  • 40C
  • 80C
  • 100C
The temperature below which a gas should be cooled, before it can be liquified by pressure only is termed as 
  • The dew point
  • The freezing point
  • The saturation point
  • The critical point
At constant volume the specific heat of a gas is 3R2 , then the value of γ will be 
  • 32
  • 52
  • 53
  • None of these
At a given volume and temperature , the pressure of a gas
  • Varies inversely as its mass
  • Varies inversely as the square of its mass
  • Varies linearly as its mass
  • Is independent of its mass
At NTP the mass of one litre of air is 1.293gm. The value of specific gas constant will be 
  • 0.29J/Kgm
  • 4.2J/Kgm
  • 8.3J/Kgm
  • 16.5Jgm
For matter to exist simultaneously in gas and liquid phases 
  • The temperature must be 0K
  • The temperature must be less than 0C
  • The temperature must be less than the critical temperature
  • The temperature must be less than the reduced temperature
The following sets of values for CV and CP of  a gas has been reported by different students. The units are cal/gm-mole-K. Which of these sets is most reliable 
  • CV=3,CP=5
  • CV=4,CP=6
  • CV=3,CP=2
  • CV=3,CP=4.2
Beryllium has roughly one-half the specific heat of water (H2O). Rank the quantities of energy input required to produce the following changes from the largest to the smallest. In your ranking, note any cases of equality.
  • raising the temperature of 1 kg of H2O from 200C to 260C
  • raising the temperature of 2 kg of H2O from 200C to 230C
  • raising the temperature of 2 kg of H2O from 10C to 40C
  • raising the temperature of 2 kg of H2O from 10C to 40C
  • raising the temperature of 2 kg of H2O from 210C to 20C
Ethyl alcohol has about one-half the specific heat of water. Assume equal amounts of energy are transferred by heat into equal-mass liquid samples of alcohol and water in separate insulated containers. The water rises in temperature by 250C. How much will the alcohol rise in temperature?
  • It will rise by 120C.
  • It will rise by 250C.
  • It will rise by 500C.
  • It depends on the rate of energy transfer.
  • It will not
    rise in temperature.
Choose the correct alternative: 
Water expands on reducing its temperature below _______ C .
  • 0
  • 4
  • 8
  • 12
A 90 cm long barometer tube contains some air above the mercury. The reading is 74.5 cm when the true pressure is 76 cm at the temperature 150C. If the reading is observed to be 75.8 cm on a day when the temperature is 50C, then the true pressure is:
  • 77.38 cm of Hg
  • 75.8 cm of Hg
  • 74 cm of Hg
  • 80 cm of Hg
The temperature of the two outer surfaces of a composite slab, consisting of two materials having coefficients of thermal conductivity K and 2K and thickness x and 4x respectively are T2 and T1 (T2>T1). The rate of heat transfer through the slab in a steady state is [A(T2T1)Kx]f, where f equals to :
26674_c0939d9749d94ad7a97c1cc7ec6df376.png
  • 1
  • 12
  • 23
  • 13
Two plates A and B of equal surface area are placed one on top of the other to form a composite plate of the same surface area. The thickness of A and B are 4.0cm and 6.0cm respectively. The temperature of the exposed surface of plate A is 10oC and that of the exposed surface of plate B is 100C. Neglect heat loss from the edges of the composite plate, the temperature of the contact surface is T1 if the plates A and B are made of the same material and T2 if their thermal conductivities are in the ratio 2:3 then
  • T1=40C
  • T1=20C
  • T2=30C
  • T2=00C

A closed container of volume 0.02 m3 contains a mixture of neon and argon gases at a temperature of 270 C and at a pressure of 1×105N/m2. The total mass of the mixture is 28 g. If the gram molecular weights of neon and argon are 20 and 40 respectively, the masses of the individual gases in the container are respectively(assuming them to be ideal) [R = 8.314 J/mol K]

  • 16 gm, 12 gm
  • 4 gm, 24 gm
  • 6 gm, 22 gm
  • 12 gm, 16 gm
One end of a thermally insulated rod is kept at a temperature T1  and the other at T2. The rod is composed of two sections of lengths l1  and  l2 and thermal conductivities K1 and K2 respectively. The temperature at the interface of two sections is :
26670_a3bc23a909fd4f17a7e5dd4e0cbddee1.png
  • K2l1T1+K1l2T2K2l1+K1l2
  • K1l2T1+K2l1T2K1l2+K2l1
  • K1l1T1+K2l2T2K1l1+K2l2
  • K2l2T1+K1l1T2K1l1+K2l2
A smooth vertical tube with two different cross-sections is open at both ends. They are fitted with  pistons of different areas of cross- section and each  piston moves within a particular section. One mole of a gas enclosed between the pistons which are tied with non-stretchable threads. The difference  in cross-sectional area of  pistons 10cm2 The mass of gas confined between  pistons is  5kg. The outside  pressure is 1 atmosphere=105N/m2. By how many degrees must the gas between pistons be heated to shift the piston by 5 cm?
Given R=8.3.

44600_eef179723d964031bc2768fe2f142c38.png
  • 0.9oC
  • 1.2oC
  • 1.5oC
  • 0.5oC

A horizontal uniform glass tube of 100cm length is sealed at both ends contains 10 cm mercury column in the middle the temperature and pressure of air on either side of mercury column are respectively 310C and 76cm of mercury if the air column at one end is kept at 00C and the other end at 2730C the pressure of air which is at 00C is (in cm of Hg )

  • 76
  • 88.2
  • 102.4
  • 122

A closed hollow insulated cylinder is filled with gas at 00C and also contains an insulated piston of negligible weight and negligible thickness at the the middle point. The gas at one side of the piston is heated to 1000C . If the piston moves 5cm, the length of the hollow cylinder is

  • 13.65 cm
  • 27.3 cm
  • 64.6 cm
  • 54.6 cm

Two identical containers each of volume V0 are joined by a small pipe. The containers contain identical gases at temperature T0 and pressure P0. One container is heated to temperature 2T0 while maintaining the other at the same temperature. The common pressure of the gas is P and n is the number of moles of gas in container at temperature 2T0.

  • P=2P0
  • P=43P0
  • n=2P0V03RT0
  • n=3P0V02RT0
Heat energy always flows from a body at low temperature to a body at high temperrature
  • True
  • False
  • Ambiguous
  • Data insufficient
Keeping the number of moles, volume and pressure the same, which of the following are the same for all ideal gas?
  • rms speed of a molecule
  • density
  • temperature
  • average of magnitude of momentum
A metal ball immersed in water weighs w1 at 5Candw2 at 50C. The coefficient of cubical expansion of metal is less than that of water. Then
  • w1>w2
  • w1<w2
  • w1=w2
  • Insufficient information
A black body is at (727)0C. It emits energy at a rate which is proportional to:
  • (727)4
  • (727)2
  • (1000)4
  • (1000)2
Three rods A,B and C have the same dimensions. Their thermal conductivities kA, kB and kC respectively. A and B are placed end to end, with the free ends kept at a certain temperature difference. C is placed separately with its ends kept at same temperature difference. The two arrangements conduct heat at the same rate kC equal to
  • kA+kB
  • kAkBkA+kB
  • 12(kA+kB)
  • 2kAkBkA+kB
During an experiment, an ideal gas is found to obey a condition P2ρ =constant [ρ=density of the gas]. The gas is initially at temperature T, pressure P and density ρ. The gas expands such that density changes to ρ2
  • The pressure of the gas changes to 2P
  • The temperature of the gas changes to 2T
  • The graph of the above process on the P-T diagram is parabola.
  • The graph of the above process on the P-T diagram is hyperbola.
When a liquid is heated in copper vessel its coefficient of apparent expansion is 6×106/oC. When the same liquid is heated is heated in a steel vessel its coefficient of apparent expansion is 24×106/oC. If the coefficient of linear expansion for copper is 18×106/oC, the coefficient of linear expansion for steel is:
  • 20×106/oC
  • 24×106/oC
  • 34×106/oC
  • 12×106/oC
The value of CpCv is 1.09 R for a gas sample in state A and is 1.00 R in state R. Let TA,TB denote the temperature and pA and pB denote the pressure of the states A and B respectively. Then
  • pA<pB and TA>TB
  • pA>pB and TA>TB
  • pA=pB and TA<TB
  • pA>pB and TA<TB
Two slabs A and B of equal surface area are placed one over the other such that their surfaces are completely in contact. The thickness of slab A is twice that of B. The coefficient of thermal conductivity or slab A is twice that of B. The first surface of slab A is maintained at 100, while the second surface of slab B is maintained at 25. The temperature at the contact of their surfaces is
  • 62.5
  • 45
  • 55
  • 85
A thermocol box has a total wall area (including the lid) of 1.0m2 and wall thickness of 3cm. It is filled with ice at 0oC. If the average temperature outside the box is 30oC throughout the day, the amount of ice that melts in one day is
(Use Kthermocol=0.03W/mK,Lfusion(ice)=3.00×105J/kg
  • 1kg
  • 2.88kg
  • 25.92kg
  • 8.64kg
One mole of an ideal gas in initial state A undergoes a cyclic process ABCA, as shown in the figure. Its pressure at A is P0. Choose the correct option(s) from the following.
1010959_2f71b2dccec543e4abb5609f8f3fb9cd.png
  • Internal energies at A and B are the same
  • Work done by the gas in process AB is PoVo ln 4
  • Pressure at C is Po4
  • Temperature at C is To4
An insulated cylindrical tube of an air-conditioner's condenser contains a hot fluid. Temperature of fluid is 500oC and outside temperature is 40oC. Hot fluid tube is very thin and is covered with 3 layers of different insulating materials. Cross-section of the tube is as shown in figure. Given r1=1cm;r2=2cm;r3=8cm;r4=64cm
KA=1W/m1oC1;KB=2W/m1oC1;KC=3W/m1oC1
Heat loss per unit length (in watts) of tube will be:
777018_4b51ae43af9f43a197fe7e4f5e3d5b04.png
  • 460ln(2)
  • 460πln(2)
  • π×460ln(2)
  • 2π×4603ln(2)
A shining metallic ball with a small black spot on its surface is heated to a very high temperature and then quickly taken to a dark room. Then:
  • Both appear equally bright
  • The spot appears brighter than the ball
  • The spot appears darker than the ball
  • Both are invisible in the dark room
Two bodies A and B have thermal emissivities of 0.01 and 0.81, respectively. The outer surface areas of the two bodies are the same. The two bodies emit total radiant power of the same rate. Wavelength λB corresponding to maximum spectral radiancy in the radiation from B shifted from the wavelength corresponding to maximum spectral radiancy in the radiation from A, by 1.00μm. If the temperature of B is 5802 K.
  • The temperature of B is 1934K
  • λB=1.5μm
  • The temperature of B is 11604K
  • The temperature of B is 2901K
An ideal gas is taken from the state A(pressure P0, volume V0) to the state B (pressure P0/2, volume 2V0) along a straight line path in the P-V diagram. Select the correct statement(s) from the following.
  • The work done by the gas in the process A to B exceeds the work that would be done by it if the system were taken from A to B along the isotherm
  • In the T-V diagram, the path AB becomes a part of the parabola
  • In the P-T diagram, the path AB becomes a part of hyperbola
  • In going from A to B, the temperature T of the gas first increases to maximum value and then decreases
The equation of state for 5 g of oxygen at a pressure P and temperature T, when occupying a volume V, will be
  • PV=(532)RT
  • PV=5RT
  • PV=(52)RT
  • PV=(516)RT
The movement of water being heated in a pot on a stove is an example of
  • conduction
  • convection
  • radiation
  • condensation
In the given figure conainer A holds an ideal gas at a pressure of 5.0×105 Pa and a temperature of 300 K. It is connected by the tin tube (and a closed valve) to container B, with four times the volume of A. Container B hold same ideal gas at a pressure of 1.0 ×105 Pa and a temperature of 400 K. The valve is opened to allow the pressure to equalize, but the temperature of each container kept constant at its initial value. The final pressure in the two containers will be close to :
1031287_7b5d344b2bc749a593ae2280f3b7272b.png
  • 2.0×105 Pa
  • 2.5×105 Pa
  • 3.0×105 Pa
  • 3.5×105 Pa
Temperature of a body increases from 73C to 127C. The radiant energy per second will become.
  • 2 times
  • 256 times
  • 16 times
  • 32 times
10g of ice at 20oC is added to 10g of water at 50oC. Specific heat of water =1cal/goC, specific heat of ice=0.5cal/goC. Latent heat of ice =80cal/g. Then resulting temperature is -
  • 20oC
  • 15oC
  • 0oC
  • 50oC
A rod of length l with thermally insulated lateral surface consists of material whose heat conductivity coefficient varies with temperature as k=α/T, where α is a constant. The ends of the rod are kept at temperature T1 and T2. Find the function T(x), where x is the distance from the end whose temperature is T1, and the heat flow density.
  • T(x)=2T1(T2T1)xf;H=αlln(T2T1).
  • T(x)=T1(T2T1)xf;H=αlln(T2T1).
  • T(x)=3T1(T2T1)xf;H=αlln(T2T1).
  • T(x)=4T1(T2T1)xf;H=αlln(T2T1).
A rod of length l and cross section area A has a variable thermal conductivity given by k=αT where α is a positive constant and T is temperature in Kelvin. Two ends of the rod are maintained at temperature T1 and T2 (T1>T2). Heat current flowing through the rod will be
  • Aα(T21T22)l
  • Aα(T21+T22)l
  • Aα(T21+T22)3l
  • Aα(T21T22)2l
A pond has an ice layer of thickness 3 cm. If K of ice is 0.005 CGS units, surface temperature of surroundings is 20C, density of ice is 0.9gm/cc, the time taken for the thickness to increase by 1 cm is
  • 30 min
  • 35 min
  • 42 min
  • 60 min
The solar constant for the earth is S. The surface temperature of the sun is T K. The sun subtends an angle θ at the earth.
  • ST4
  • ST2
  • Sθ2
  • Sθ
Three rods of a same material same area of cross-section but different lengths 10 cm, 20 cm, and 30 cm are connected at a point as shown. What is a temperature of junction O?
1039086_0f7a7f2efba645eeb105001a46abb508.png
  • 19.2
  • 16.4
  • 11.5
  • 22
0:0:1


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