JEE Questions for Physics Thermal Properties Of Matter Quiz 3 - MCQExams.com

The plots of intensity of radiation versus wavelength of three black bodies at temperatures T1, T2 and T3 are shown. Then,
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  • T3 > T2 > T1
  • T1 > T2 > T3
  • T2 > T3 > T1
  • T1 > T3 > T2
  • T3 > T1 > T2
If a black body emits 0.5 J of energy per second when it is at 27°C, then the amount of energy emitted by it when it is at 627°C will be
  • 40.5 J
  • 162 J
  • 13.5 J
  • 135 J
The intensity of radiation emitted by the sun has its maximum value at a wavelength of 510 nm and that emitted by the North star has the maximum value at wavelength of 350 nm. If these stars behave like black bodies, then the ratio of surface temperatures of the sun and North star is
  • 1.46
  • 0.69
  • 1.21
  • 0.83
The maximum energy in thermal radiation from a source occurs at the wavelength 4000 A°. The effective temperature of the source is
  • 7325 K
  • 800 K
  • 104 K
  • 106 K
A body cools from 62° C to 50°C in 10 min and to 42°C in the next 10 min. The temperature of the surrounding is
  • 16° C
  • 26° C
  • 36° C
  • 21° C
A black body emits radiations of maximum intensity for the wavelength of 5000 A when the temperature of the body is 1227°C. If the temperature of the body is increased by 1000°C, the maximum intensity would be observed at
  • 1000 A°
  • 2000 A°
  • 5000 A°
  • 3000 A°
Wien's displacement law for emission of radiation can be written as
  • λmax is proportional to absolute temperature (T)
  • λmax is proportional to square of absolute temperature (T
  • λmax is inversely proportional to absolute temperature (T)
  • λmax is inversely proportional to square of absolute temperature (T( where, λmax = wavelength whose energy density is greatest)
Two circular discs A and B with equal radii are blackened. They are heated to same temperature and are cooled under identical conditions. What inference do you draw from their cooling curves?
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  • A and B have same specific heats
  • Specific heat of A is less
  • Specific heat of B is less
  • None of the above
Two bodies A and B having temperatures 327°C and 427°C are radiating heat to the surrounding. The surrounding temperature is 27°C. The ratio of rate of heat radiation of A to that of B is
  • 0.52
  • 0.31
  • 0.81
  • 0.42

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    Physics-Thermal Properties of Matter-90768.png

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A body cools from 60°C to 50°C in 10 min. If the room temperature is 25°C and assuming Newton's law of cooling to hold good, the temperature of the body at the end of the next 10 min will be
  • 45° C
  • 42.85° C
  • 40° C
  • 38.5° C
If the temperature of the sun were to increase from T to 2T and its radius from R to 2R, then the ratio of the radiant energy received on the earth to what it was previously, will be
  • 4
  • 16
  • 32
  • 64
Assuming the sun to be a spherical body of radius R at a temperature of T K, evaluate the total radiant power, incident on the earth, at a distance r from the sun

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    Physics-Thermal Properties of Matter-90773.png

  • Physics-Thermal Properties of Matter-90774.png

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Newton's law of cooling holds good only, if the temperature difference between the body and the surroundings is
  • less than 10°C
  • more than 10°C
  • less than 100°C
  • more than 100°C
Flash light equipied with a new set of batteries, produces bright white light. As the batteries wear out
  • the light intensity gets reduced with no change in its colour
  • light colour changes first to yellow and then red with no change in intensity
  • it stops working suddenly while giving white light
  • colour changes to red and also intensity gets reduced
The wavelength of the radiation emitted by a body depends upon
  • the nature of the surface
  • the area of the surface
  • the temperature of the surface
  • All of the above
Two identical bodies have temperatures 277°C and 67°C. If the surroundings temperature is 27°C, the ratio of loss of heats of the two bodies during the same interval of time is (approximately)
  • 4 : 1
  • 8 : 1
  • 12 : 1
  • 19 : 1
The spectral energy distribution of a star is maximum at twice temperature as that of the sun. The total energy radiated by the star is
  • twice as that of the sun
  • same as that of the sun
  • sixteen times as that of the sun
  • one-sixteenth of the sun
The coefficient of volume expansion of a liquid is 49 × 10-5 K-1. Calculate the fractional change in its density, when the temperature is raised by 30°C.
  • 7.5 x 10-3
  • 3.0 x 10-3
  • 1.5 x 10-2
  • 1.1 x 10-3
A bimetallic strip consists of metals X and Y. It is mounted rigidly at the base as shown. The metal X has a higher coefficient of expansion compared to that for metal Y. When bimetallic strip is placed in a cold bath
Physics-Thermal Properties of Matter-90776.png
  • it will bend towards the right
  • it will bend towards the left
  • it will not bend but shrink
  • it will neither bend nor shrink
Two slabs are of the thicknesses d1 and d2. Their thermal conductivities are K1 and K2 respectively. They are in series. The free ends of the combination of these two slabs are kept at temperatures θ1 and θ2. Assume θ1> θ2. The temperature θ of their common junction is

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    Physics-Thermal Properties of Matter-90778.png

  • Physics-Thermal Properties of Matter-90779.png

  • Physics-Thermal Properties of Matter-90780.png
The temperature of the two outer surfaces of a composite slab, consisting of two materials having coefficients of thermal conductivities 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
Physics-Thermal Properties of Matter-90781.png
  • 1
  • 1/2
  • 2/3
  • 1/3
The figure shows a system of two concentric spheres of radii r1 and r2 and kept at temperatures T1 and T2 respectively. The radial rate of flow of heat in a substance between the two concentric spheres, is proportional to
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    Physics-Thermal Properties of Matter-90784.png

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  • Physics-Thermal Properties of Matter-90786.png

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    Physics-Thermal Properties of Matter-90790.png

  • Physics-Thermal Properties of Matter-90791.png

  • Physics-Thermal Properties of Matter-90792.png
If a piece of metal is heated to temperature θ and then allowed to cool in a room which is at temperature θ0. The graph between the temperature T of the metal and time t will be closed to

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    Physics-Thermal Properties of Matter-90794.png

  • Physics-Thermal Properties of Matter-90795.png

  • Physics-Thermal Properties of Matter-90796.png
A liquid in a beaker has temperature θ(T) at time t and θ0 is temperature of surroundings, then according to Newton\'s law of cooling, the correct graph between loge (θ - θ0) and t is

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    Physics-Thermal Properties of Matter-90798.png

  • Physics-Thermal Properties of Matter-90799.png

  • Physics-Thermal Properties of Matter-90800.png
Assuming the sun to have a spherical outer surface of radius r, radiating like a black body at temperature t°C, the power received by a unit surface, (normal to the incident rays) at a distance R from the centre of the sun is, where, σ is the Stefan's constant.

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    Physics-Thermal Properties of Matter-90802.png

  • Physics-Thermal Properties of Matter-90803.png

  • Physics-Thermal Properties of Matter-90804.png
The surface area of a black body is 5 × 10-4 m2 and its temperature is 727°C. The energy radiated by it per min is (σ = 5.67 × 10-8 Jm-2 – s-1 – K-4)
  • 1.7 × 103 J
  • 2.5 × 102 J
  • 8 × 103 J
  • 3 × 104 J
  • None of these
Two solid spheres A and B made of the same material have radii rA and rB respectively. Both the spheres are cooled from the same temperature under the conditions valid for Newton's law of cooling. The ratio of the rate of change of temperature of A and B is

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    Physics-Thermal Properties of Matter-90807.png

  • Physics-Thermal Properties of Matter-90808.png

  • Physics-Thermal Properties of Matter-90809.png
Variation of radiant energy E, emitted by the sun, filament of tungsten lamp and welding arc as a function of its wavelength is shown in figure. Which of the following option is the correct match ?
Physics-Thermal Properties of Matter-90810.png
  • Sun – T1, tungsten filament – T2, welding arc – T3
  • Sun – T2, tungsten filament – T1, welding arc – T3
  • Sun – T3, tungsten filament – T2, welding arc – T1
  • Sun – T1, tungsten filament – T3, welding arc – T2
A black body is heated from 27°C to 927°C. The ratio of radiation emitted will be
  • 1 : 4
  • 1 : 8
  • 1 : 16
  • 1 : 256
A bucket full of hot water is kept in a room. It cools from 75°C to 70°C in t1 min, from 70°C to 65°C in t2 min and from 65°C to 60°C in t3 min. Then ,
  • t1 < t2 < t3
  • t1 = t2 = t3
  • t1 < t2 > t3
  • t1 > t2 > t3
The following four wires of length L and radius r are made of the same material. Which of these will have the largest extension when the same tension is applied?
  • L = 40 cm, r = 0.20 mm
  • L = 100 cm, r = 0.5 mm
  • L = 200 cm, r = 1 mm
  • L = 300 cm, r = 1.5 mm.
The relation between Young’s modulus (Y), modulus of rigidity (η) and poisson’s ratio (σ) is
  • Y=2 η (1 – σ)
  • Y=2 η (1 + σ)
  • Y= η(1– 2σ)
  • Y =2η(1+2 σ)
A wire of length L and of area of cross-section A is stretched through a certain length l. If Y is Young’s modulus of the material of the wire, then the force constant of the wire is

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    Physics-Thermal Properties of Matter-90814.png

  • Physics-Thermal Properties of Matter-90815.png

  • Physics-Thermal Properties of Matter-90816.png
A uniformly tapering vessel shown in Fig., is filled with liquid of density 900 kg/m3. The force that acts on the base of the vessel due to liquid is (take g = 10 m/s2)
Physics-Thermal Properties of Matter-90818.png
  • 3.6 N
  • 7.2 N
  • 9.0 N
  • 12.6 N
An open vessel containing water is given a constant acceleration a in the horizontal direction. Then the free surface of water gets sloped with the horizontal at an angle θ, given by

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    Physics-Thermal Properties of Matter-90821.png

  • Physics-Thermal Properties of Matter-90822.png

  • Physics-Thermal Properties of Matter-90823.png
An ice block floats in a liquid whose density is less than water. A part of block is outside the liquid. When whole of ice has melted, the liquid level will
  • rise
  • go down
  • remain same
  • first rise then go down
Fig. shows the vertical cross section of a vessel filled with a liquid of density ρ. The normal thrust per unit area on the walls of the vessel at point P, as shown will be
Physics-Thermal Properties of Matter-90825.png
  • h ρ g
  • H ρ g
  • (H – h) ρ g
  • (H – h) ρ g cos θ
The SI unit of mechanical equivalent of heat is
  • Joule × Calorie
  • Joule/Calorie
  • Calorie × Erg
  • Erg/Calorie
Surface tension of a liquid is due to
  • gravitational force between molecules
  • electrical force between molecules
  • adhesive force between molecules
  • cohesive force between molecules
Kerosene oil rises up in a wick of a lantern because of
  • diffusion of the oil through the wick
  • surface tension
  • buoyant force of air
  • the gravitational pull of the wick.
At critical temperature, the surface tension of a liquid is
  • zero
  • infinity
  • the same as that at any other temperature
  • cannot be determined
When a pinch of salt or any other salt which is soluble in water is added to water, its, surface tension
  • increases
  • decreases
  • may increase of decrease depending upon salt
  • none of the above.
The force of viscosity is
  • gravitational
  • weak
  • electromagnetic
  • nuclear
Rain drops fall from a great height under gravity-Check the correct statement:
  • Their velocity continuously increases till they hit the earth with the same final velocity
  • They fall with a terminal velocity which is different for drops of different sizes
  • They fall with a terminal velocity which is the same for every drop
  • Their velocity goes on increasing continuously till they hit the earth, and the final velocity of each drop is different.
The coefficient of viscosity for hot air is
  • greater than the coefficient of viscosity for cold air
  • smaller than the coefficient of viscosity for cold air
  • same as the coefficient of viscosity for cold air
  • increases or decreases depending on the external pressure.
In Bernoulli’s theorem which of the following is conserved
  • mass
  • linear momentum
  • energy
  • angular momentum.
The unit of the universal gas constant in S.I. system is
  • calories per degree Celsius
  • joule per mole

  • Physics-Thermal Properties of Matter-90827.png
  • Joule per kg.
The relation PV = RT can describe the behaviour of a real gas at
  • high temperature and high density
  • high temperature and low density
  • low temperature and low density
  • low temperature and high density
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