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CBSE Questions for Class 11 Engineering Physics Thermal Properties Of Matter Quiz 13 - MCQExams.com

The pressure of an ideal gas veries according to the law P=P0AV2 where P0 and A are positive constants. What is the highest temperature that can be attained by the gas?
  • P0nRP0A
  • P0nRP02A
  • 2P0nRP02A
  • 2P03nRP03A
Radiation emitted from a radioactive element, of half life period of 30 min, are measured by a Geigar - Mullar counter. The count rate of the sample reduces to 5 disintegrations /sec. in 2hrs. then the initial count rate in disintegration/sec is :-
  • 805
  • 200
  • 250
  • 40
Two metallic sphere S1 and S2 are made of the same material and have got identical surface finish.The mass of S1 is thrice that of S2.Both the sphere are heated to the same high temperature and placed in the same room having lower temperature but are thermally insulated from each other.The ratio of the initial rate of cooling of S1 to that S2 is :
  • 13
  • 13
  • 31
  • (13)13
Consider the situation as shown in fig. Calculate the amount of heat flowing per second through a cross section of the bent part, if the total heat taken out per second from the end at 100oC is 130 J
1140617_b93d41d4b2424f888d2200e56db31870.png
  • 130 J
  • 60 J
  • 70 J
  • 80 J
A metre scale made of steel is calibrated at 20C to give correct reading. Find the distance between 50cm mark and 51cm mark if the scale is used at 10C. Coefficient of linear expansion of steel is 1.1×105oC1.
  • 1.000 11 cm
  • 1.11 cm
  • 0.999m
  • 1.01 m
Two closed containers of equal volume filled with air at pressure P0 and temperature T0. Both are connected by  narrow tube. If one of the container is maintained at temperature T0 and another at temperature T, then new pressure in the containers will be 
  • 2P0TT+T0
  • P0TT+T0
  • P0T2(T+T0)
  • T+T0P0
A hot body is placed in cooler surrounding. When the hot body temperature 75C, the rate of cooling is 4C/min. When it is 55C, the rate of cooling is 2C/min. The temperature of the surroundings is
  • 20C
  • 25C
  • 30C
  • 35C
Compare rate of radiation of metal sphere at 6270C annd 3270C.
  • 0.7 : 1
  • 3 : 1
  • 63 : 1
  • 5.063 : 1
In the given figure, if the heat flowing through the 5Ω resistance is 10 calorie then how much heat is flowing through the 4Ω resistance ?
1129746_ba4b1253492c4e23a5d135cc077b5afd.png
  • 1 calorie
  • 2 calorie
  • 3 calorie
  • 4 calorie
Two rods with the same dimensions have thermal conductivity in the ratio 1: 2. They are arranged between heat reservoirs with the same temperature difference, in two different configurations, in two different configurations. A and B. The rates of heat flow in A and B are IA and IB respectively. The ratio IAIB is equal to 
1120486_fcc4f7df975444f09c1c1c16c45e758d.png
  • 1: 2
  • 1: 3
  • 2: 5
  • 2: 9
Two bodies A and B having equal surface areas are maintained at temperatures 10C and 20C. The thermal radiation emitted in a given time by A and B are in the ratio
  • 1:1.15
  • 1:2
  • 1:4
  • 1:16
Two rods A and B of same length and radius are joined together. the thermal conductivity of A and B are 2K and K. Under steady state conditions, if the temperature difference between the open ends of A and B is 36C, the temperature difference across 'A' is:
  • 12C
  • 18C
  • 24C
  • 9C
Two identical square rods of metal are welded end to end as shown in figure (a). 20 calories of heat flows through it in 4 minutes. if the rods are welded as shown in figure (b), the same amount of heat will flow through the rods in
1216084_0f8d4f1267b7494c9e229dd3da3509dd.png
  • 1 minute
  • 2 minutes
  • 4 minutes
  • 16 minutes
In a container of negligible heat capacity 100gm of a liquid at 20C is heated. Specific heat of the liquid varies with temperature given as s=(100T+500)J/kgC where T is inC . Find the amount of heat required to raise the temperature of the liquid to 40C
  • 5000J
  • 6000J
  • 7000J
  • 8000J
A copper block A of mass 500 gm and Sp heat 0.1 cal/gm/C is heated from 30C to 40C. Another identical copper block B of same mass is heated from 35C to 40C. The ratio of their thermal capacities is: 
  • 1 : 2
  • 2 : 1
  • 1 : 1
  • 1 : 4
A copper bar 10 cm long has its ends passed against copper tanks at 0oC and 100oC. The ends are separated by layers of dust 0.1 mm thick. If conductivity of dust is 0.001 times that of copper, the temperature of end P and Q of bar are [Take rate of flow of heat constant from P to Q]
1211132_a589906d52a64746aace314335c08ae8.png
  • 33.3oC and 66.7oC
  • 66.7oC and 33.3oC
  • 75oC and 25oC
  • 60oC and 40oC
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 the sections is 
1211231_ee12e533aa974cc4883c286a6e69d5ca.jpg
  • (K2L2T1+K1L1T2)(K1L1+K2L2)
  • (K2L1T1+K1L2T2)(K2L1+K1L2)
  • (K1L2T1+K2L1T2)(K1L2+K2L1)
  • (K1L1T1+K2L2T2)(K1L1+K2L2)
The pressure of the gas contained in a closed vessel is increased by 0.4% when heated by 1oC. The initial temperature of the gas must be
  • 1250K
  • 250K
  • 2500K
  • 25oC
When is the temperature at its peak? what is its value then?
  • 4hrs,106.4oF
  • 3hrs,102.4oF
  • 2hrs,104.4oF
  • 1hrs,98oF
A beaker of height H is made up of a material whose coefficient of linear thermal expansion is 3α. It is filled up to the brim by a liquid whose coefficient of thermal expansion is α. If now the beaker along with its contents is uniformly heated through a small temperature T the level of liquid will reduce by (given α<<1.)
  • αTH
  • 3αTH
  • 9αTH
  • 6αTH
A crystal has a coefficient of expansion 1.3×108 in one direction and 2.31×107 in every direction at right angles to it. Then the cubical coefficient of expansion is :
  • 4.62×107
  • 2.44×107
  • 4.75×107
  • 2.57×107
If the temperature of a hot body is increased by 50% then the increase in the quantity of emitted heat radiation will be
  • 125%
  • 200%
  • 300%
  • 400%
When a body is placed in surrounding at a constant temperature of 20C, and heated by a 10-W, heater, its temperature remains constant at 40C. If the temperature 
  • 3000 J
  • 3600 J
  • 4500 J
  • 5400 J
In on heating liquid through 80oC, the mass expelled is (1/100)th of mass still remaining, the coefficient of apparent expansion of liquid is:
  • 1.25×104/oC
  • 12.5×104/oC
  • 1.25×105/oC
  • None of these
Find the temperature at which the thermometer reads correctly?
  • 60C
  • 40C
  • 50C
  • 55C
Two metal cubes A and B of same size are arranged as shown in the figure. The extreme ends of the combination are maintained at the indicated temperatures. The arrangement is thermally insulated. The coefficients of thermal conductivity of A and B are 300 W/m0C and 200 W/m0C, respectively. After steady state is reached, the temperature of the interface will be 
1260124_7d34c99e8bff4a1c8bcf3b5186efa3c6.PNG
  • 450C
  • 900C
  • 300C
  • 600C
Radius of the sun is 7×108m and the energy radiated by it is 38×1028W. Calculate the magnitude of energy propagation poynting vector (i.e., energy flowing per second per unit area) on the surface of sun:-
  • 6.17×108W/m2
  • 6.17×109W/m2
  • 6.17×1010W/m2
  • 6.17×1011W/m2
Three rods AB,BC and AC having thermal resistances of 10 units, 10 units and 20 units, respectively, are connected as shown in the figure. Ends A and C are maintained at constant temperatures of 100C and 0C, respectively. The rate at which the heat is crossing junction B is:
1295112_f70f3960c99542c2967c308a37e32f13.PNG
  • 5 units
  • 10 units
  • 20 units
  • 7.5 units
One end of a 0.25 m long metal bar is in steam and the other end is in contact with ice. If 12 g of ice melts per minute , What is the thermal conductivity of the metal ? Given cross-section of the bar=5×104m2 and latent heat of ice is 80 cal/g
  • 80cal/sm C
  • 90cal/sm C
  • 70cal/sm C
  • 60cal/sm C
If the system takes 100 cal. heat, and releases 80 cal to sink, if source temperature is 127oC find the sink temperature :- 
  • 47oC
  • 127oC
  • 67oC
  • 107oC
The value of universal gas constant is R=8.3 J/K - mol. The value of R in atmosphere litre per kelvin mol
  • 8.12
  • 0.00812
  • 81.2
  • 0.082
A long mercury glass tube with a uniform capillary bore has in it a thread of mercury which is 1m long at 0C. What will be its length at 100C is the real coefficient of expansion of mercury is 0.000182C1 and coefficient of cubical expansion of glass equal to 0.000025C1.
  • 0.516 m
  • 1.016 m
  • 1.516 m
  • 2.016 m
At what temperature is the r.m.s velocity of a hydrogen molecule equal to that of an oxygen molecule at 47oC?
  • 80K
  • 73K
  • 3K
  • 20K
A glass bottle of capacity 50 cc at 0C is filled with paraffin at 15C. Given that the density of paraffin at 0C is 0.82 g/cc, coefficient of expansion of paraffin is 0.0009C and coefficient of linear expansion is 0.000009C, the mass of paraffin in the bottle is:-
  • 40.5 g
  • 54.0 g
  • 50.4 g
  • 5.04 g
Two metal spheres have radii r and 2r and they emit thermal radiation with maximum intensities at wavelengths λ and 2λ respectively. The respective ratio of the radiant energy emitted by them per second will be
  • 4 : 1
  • 1 : 4
  • 16 : 1
  • 8 : 1
4.0g of a gas occupies 22.4litres at NTP. The specific heat capacity of the gas at constant volume is5.0JK1mol1. If the speed of sound in this gas at NTP is 952ms1, then the heat capacity at constant pressure is(Take gas constant R=8.3JK1mol1)
  • 8.5JK1mol1
  • 8.0JK1mol1
  • 7.5JK1mol1
  • 7.0JK1mol1
Three closed vessels A, B and C are at the same temperature T and contain gases which obey the Maxwellian distribution of velocities, Vessel A contains only O2 B only N2 and C a mixture of equal quantities of O2 and  N2 If the average speed of the O2 molecules in vessel A is V1, that of N2 molecules in vessel B is V2 the average speed of the O2 molecules in vessel C is ( where M is the mass of an oxygen molecule) 
  • (V1+V2)/2
  • V1
  • (V1V2)1/2
  • 3kT/M
Eleven identical rods are arranged as shown in figure. each rod has length l, cross-sectional area A and thermal conductivity of material K. ends A and F are maintained at temperatures T1 and T2(<T1), respectively. if lateral surface of each rod is thermally insulated, the rate of heat transfer (dQdt) in each rod is 
1382502_e6dfd04434374b918b5e1a0dfc84d980.PNG
  • (dQdt)AB=(dQdt)CD
  • (dQdt)BE=27(T1T2)KAl
  • (dQdt)CH(dQdt)DG
  • (dQdt)BC=(dQdt)DC
Two contains are filled, each with a different gas,The two containers are at the same temperature.Suppose that the molecular weight of the two gases are MAandMB the average moments (in magnitude) of the molecules are related as:
  • PA=PB
  • PA=MBMAPB
  • PA=(MAMB)1/2PB
  • PA=(MBMA)1/2PB
A 2 cm thick slab of commercial thermocole 100cm2 in cross -section and having thermal conductivity 2×104 cal sec10C1 has insulating regions diferring by 100C. The quality of heat flowing through it in a day
  • 20.4 K cal
  • 43.2 K cal
  • 86.4 K cal
  • 23.2 K cal
A motor - car tyre has a pressure of 2 atm at 27C. It suddenly bursts. If (CpCv=1.4) for air, find resulting temp :-
  • 24 K
  • 27C
  • -27C
  • 246C
Which of the following diagrams depicts ideal gas behaviour?
A rod of length L with sides fully insulated is of a material whose thermal conductivity varies with temperature as K=αT, where α is a constant. The ends of the rod are kept at temperature T1 and T2. The temperature T at x, where x is the distance from the end whose temperature is T1 is 
  • T1(T2T1)xL
  • xLlnT2T1
  • T1eT2xT1L
  • T1+T2T1Lx
The density of a liquid at 100C is 8.0g/cm3and at 0C is 8.4g/cm3 , the coefficient of cubical expansion of the liquid is
  • 104/C
  • 5×104/0C
  • 8×104/C
  • 4×104/0C
The thermal radiation from a hot body travels with a speed of
  • 330ms1
  • 2×108ms1
  • 1200ms1
  • 230ms1
  • 3×108ms1
With cold wind keeping the surface at 20oC a layer of ice on a pond grows in thickness from 20 mm to 21 mm in 10 min. Later with the surface at the same temperature it will grow from 40 mm to 42 mm in approximately
  • 10 min
  • 10.2 min
  • 20 min
  • 40 min
A refrigerator is thermally equivalent to a box of cork board 90mm thick and m2 in inner surface area, the thermal conductivity of cork being 0.05W/mK . The motor of the refrigerator runs 15% of the time while the door closed. The inside wall of the door, when it is closed,is kept, on an average, 22C below the temperature of the outside wall. The rate at which heat is taken from the interior wall while the motor is running is
  • 400W
  • 500W
  • 300W
  • 250W
A and B are two points on a uniform metal ring whose centre is O. The angle AOB = θ. A angle B are maintained at two different constant temperatures. When θ=180o, the rate of total heat flow from A to B is 1.2W. When θ=90o then this rate will be
  • 0.6watt
  • 0.9watt
  • 1.6watt
  • 1.8watt
A body cools from 62   C  to   50C  in 10 minutes and then to 42 C in next 10 minutes.  The temperature of surrounding is : 
  • 23C
  • 27C
  • 26C
  • 24C
Water standing in the open at 320C evaporates because of the escape of some of the surface molecules. The heat of vaporization (540cal/g) is approximately equal to ϵn, where ϵ is the average energy of the escaping molecules and n is the number of molecules per gram. The value of ϵ is close to
  • 1.62×1020J
  • 14.23×1020J
  • 6.75×1020J
  • 8.31×1020J
0:0:1


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