# MCQs For NCERT Class 11 Physics Chapter 11 Thermal Properties of Matter

Please refer to the MCQ Questions for Class 11 Physics Chapter 11 Thermal Properties of Matter with Answers. The following Thermal Properties of Matter Class 11 Physics MCQ Questions have been designed based on the latest syllabus and examination pattern for Class 11. Our experts have designed MCQ Questions for Class 11 Physics with Answers for all chapters in your NCERT Class 11 Physics book.

## Thermal Properties of Matter Class 11 MCQ Questions with Answers

See below Thermal Properties of Matter Class 11 Physics MCQ Questions, solve the questions and compare your answers with the solutions provided below.

Question In order that the heat flows from one part of a solid to another part, what is required?
(a) Uniform density
(d) Uniform temperature

B

Question. The sprinkling of water slightly reduces the temperature of a closed room because
(a) temperature of water is less than that of the room
(b) specific heat of water is high
(c) water has large latent heat of vaporisation
(d) water is a bad conductor of heat

C

Question. Which of the following is not close to a black body?
(a) Black board paint
(b) Green leaves
(c) Black holes
(d) Red roses

A

Question. According to Newton’s law of cooling, the rate of cooling of a body is proportional to (Dq)n, where Dq is the difference of the temperature of the body and the surroundings, and n is equal to
(a) two
(b) three
(c) four
(d) one

D

Question. A metallic rod l cm long, A square cm in cross-section is heated through tºC. If Young’s modulus of elasticity of the metal is E and the mean coefficient of linear expansion is a per degree celsius, then the compressional force required to prevent the rod from expanding along its length is
(a) E A ∝ t
(b) E A ∝ t/(1 + at)
(c) E A ∝ t/(1 – ∝ t)
(d) E l ∝ t

A

Question. A black body rediates energy at the rate of E watt per metre2 at a high temperature T K. when the temperature is reduced to (T/2) K, the radiant energy will be
(a) E/16
(b) E/4
(c) E/2
(d) 2E

A

Question. Two straight metallic strips each of thickness t and length l are rivetted together. Their coefficients of linear expansions are a1 and a2 . If they are heated through temperature DT, the bimetallic strip will bend to form an arc of radius
(a) t /{α1 + α2 )ΔT}
(b) t /{(α2 – α1)ΔT}
(c) t (α1 – α2 )ΔT
(d) t (α2 – α1)ΔT

B

Question. Two solid spheres, of radii R1 and R2 are made of the same material and have similar surfaces. The spheres are raised to the same temperature and then allowed to cool under identical conditions. Assuming spheres to be perfect conductors of heat, their initial rates of loss of heat are
(a) R12 / R22
(b) R1 / R2
(c) R2 / R1
(d) / R2/R12

A

Question. A radiation of energy E falls normally on a perfectly reflecting surface. The momentum transferred to the surface is
(a) Ec
(b) 2E/c
(c) E/c
(d) E/c2

B

Question. For the construction of a thermometer, one of the essential requirements is a thermometric substance which
(a) remains liquid over the entire range of temperatures to be meaured .
(b) has property that varies linearly with temperature
(c) has a property that varies with temperature
(d) obey Boyle’s law

C

Question. The temperature of stars is determined by
(a) Stefan’s law
(b) Wien’s displacement law
(c) Kirchhoff’s law
(d) Ohm’s law

B

Question. The temperature of the Sun is measured with
(a) platinum thermometer
(b) gas thermometer
(c) pyrometer
(d) vapour pressure thermometer.

C

Question. Which of the following circular rods, (given radius r and length l) each made of the same material and whose ends are maintained at the same temperature will conduct most
heat?
(a) r = 2r0; l = 2l0
(b) r = 2r0; l = l0
(c) r = r0; l = 2l0
(d) r = r0; l = l0

B

Question. If the temperature of a black body increases from 7°C to 287°C, then the rate of emission of radiation energy is:
(a) 8 times
(b) 16 times
(c) 2 times
(d) 4 times

B

Question. The radiation from the sun, incident normally at the surface of the earth is 20kcal /m2 min.
What would have the radiant energy, incident normally on the earth if the sun had a temperature, twice of the present one ?
(a) 80 kcal /m2 min
(b) 320kcal /m2 min
(c) 160kcal /m2 min
(d) 40kcal /m2 min

B

Question. The thermal conductivity of a rod is 2. What is its thermal resistivity ?
(a) 0.5
(b) 1
(c) 0.25
(d) 2

A

Question. At a certain temperature for given wave length , the ratio of emissive power of a body to emissive power of black body in same circumstances is known as
(a) relative emissivity
(b) emissivity
(c) absorption coefficient
(d) coefficient of reflection

C

Question. If a liquid is heated in weightlessness, the heat is transmitted through
(a) conduction
(b) convection
(d) None of these, because the liquid cannot be heated in weightlessness.

A

Question. When a body is heated, which colour corresponds to high temperature
(a) red
(b) yellow
(c) white
(d) orange

C

Question. The two ends of a rod of length L and a uniform crosssectional area A are kept at two temperatures T1 and T2 (T1 > T2). The rate of heat transfer, dQ /dt through the rod in a steady state is given by
(a) dQ/dt =  k (T1 – T2 ) /LA
(b) dQ/dt =  kLA (T1 – T2 )
(c) dQ/dt =  kA (T1 – T2 ) /L
(a) dQ/dt =  k (T1 – T2 ) /A

C

Question. Two rods of the same length and areas of cross-section A1 and A2 have their ends at the same temperature. K1 and K2 are the thremal conductivities of the two rods. The rate of flow of heat is same in both rods if
(a) A1 /A2 =K1/K2
(b) A1 /A2 =K2/K1
(c)  A1 A2 = K1 K2
(d) A1 K1 2 = A2 K22

B

Question. The resistance of a resistance thermometer has values 2.71 and 3.70 ohms at 10ºC and 100ºC respectively. The temperature at which the resistance is 3.26 ohm is
(a) 40ºC
(b) 50ºC
(c) 60ºC
(d) 70ºC

C

Question. The temperature of an iron block is 140ºF. Its temperature on the Celsius scale is
(a) 60º
(b) 160º
(c) 140º
(d) 132º

A

Question. Steam at 100°C is passed into 20 g of water at 10°C.
When water acquires a temperature of 80°C, the mass of water present will be [Take specific heat of water = 1 cal g–1 °C–1 and latent heat of steam = 540 cal g–1]
(a) 24 g
(b) 31.5 g
(c) 42.5 g
(d) 22.5 g

D

Question. If 1 g of steam is mixed with 1 g of ice, then resultant temperature of the mixture is
(a) 100°C
(b) 230°C
(c) 270°C
(d) 50°C

A

Question. 10 gm of ice cubes at 0°C are released in a tumbler (water equivalent 55 g) at 40°C. Assuming that negligible heat is taken from the surroundings, the temperature of water in the tumbler becomes nearely (L = 80 cal/g)
(a) 31°C
(b) 22°C
(c) 19°C
(d) 15°C

B

Question. A spherical black body with a radius of 12 cm radiates 450 watt power at 500 K. If the radius were halved and the temperature doubled, the power radiated in watt would be
(a) 450
(b) 1000
(c) 1800
(d) 225

C

Question. A black body is at a temperature of 5760 K.
The energy of radiation emitted by the body at wavelength 250 nm is U1, at wavelength 500 nm is U2 and that at 1000 nm is U3. Wien’s constant, b = 2.88 × 106 nm K. Which of the following is correct?
(a) U1 > U2
(b) U2 > U1
(c) U1 = 0
(d) U3 = 0

B

Question. The two ends of a metal rod are maintained at temperatures 100°C and 110°C. The rate of heat flow in the rod is found to be 4.0 J/s. If the ends are maintained at temperatures 200°C and 210°C, the rate of heat flow will be
(a) 8.0 J/s
(b) 4.0 J/s
(c) 44.0 J/s
(d) 16.8 J/s

B

Question. A piece of iron is heated in a flame. It first becomes dull red then becomes reddish yellow and finally turns to white hot. The correct explanation for the above observation is possible by using
(a) Kirchhoff’s Law
(b) Newton’s Law of cooling
(c) Stefan’s Law
(d) Wien’s displacement Law

D

Question. A slab of stone of area 0.36 m2 and thickness 0.1 m is exposed on the lower surface to steam at 100°C. A block of ice at 0°C rests on the upper surface of the slab. In one hour 4.8 kg of ice is melted. The thermal conductivity of slab is (Given latent heat of fusion of ice = 3.36 × 105 J kg–1)
(a) 1.24 J/m/s/°C
(b) 1.29 J/m/s/°C
(c) 2.05 J/m/s/°C
(d) 1.02 J/m/s/°C

A

Question. A cylindrical metallic rod in thermal contact with two reservoirs of heat at its two ends conducts an amount of heat Q in time t. The metallic rod is melted and the material is formed into a rod of half the radius of the original rod. What is the amount of heat conducted by the new rod, when placed in thermal contact with the two reservoirs in time t?
(a) Q/4
(b) Q/16
(c) 2Q
(d) Q/2

B

Question. A black body at 227°C radiates heat at the rate of 7 cals/cm2s. At a temperature of 727°C, the rate of heat radiated in the same units will be
(a) 50
(b) 112
(c) 80
(d) 60

B

Question. Steam is passed into 22 gm of water at 20ºC. The mass of water that will be present when the water acquires a temperatue of 90ºC (Latent heat of steam is 540 cal/g) is
(a) 24.83 gm
(b) 24 gm
(c) 36.6 gm
(d) 30 gm

A

Question. A cylindrical rod of aluminium is of length 20 cms and radius 2 cms. The two ends are maintained at temperatures of 0ºC and 50ºC the coefficient of thermal conductivity is 0.5 cal / cm×sec ×ºC Then the thermal resistance of the rod in cal / sec ×ºC is
(a) 318
(b) 31.8
(c) 3.18
(d) 0.318

D

Question. A piece of ice falls from a height h so that it melts completely.
Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of h is :
[Latent heat of ice is 3.4 × 105 J/kg and g = 10 N/kg]
(a) 34 km
(b) 544 km
(c) 136 km
(d) 68 km

C

Question. A black body is at a temperature of 5760 K. The energy of radiation emitted by the body at wavelength 250 nm is U1,at wavelength 500 nm is U2 and that at 1000 nm is U3. Wien’s constant, b = 2.88 × 106 nmK. Which of the following is correct ?
(a) U1 = 0
(b) U3 = 0
(c) U1 > U2
(d) U2 > U1

D

Question. A spherical black body with a radius of 12 cm radiates 450 watt power at 500 K. If the radius were halved and the temperature doubled, the power radiated in watt would be :
(a) 450
(b) 1000
(c) 1800
(d) 225

C

Question. A metal ball of surface area 200 square cm, temperature 527ºC is surrounded by a vessel at 27ºC. If the emissivity of the metal is 0.4, then the rate of loss of heat from the ball is approximately σ = 5.67X10-8 joule / m2 X sec X K2
(a) 108 joule
(b) 168 joule
(c) 182 joule
(d) 192 joule

C

Question. The rate of radiation of a black body at 0ºC is E joule per sec.
Then the rate of radiation of this black body at 273ºc will be
(a) 16 E
(b) 8 E
(c) 4 E
(d) E

A

Question. A bimetallic strip is made of aluminium and steel (aAl >∝steel). On heating, the strip will
(a) remain straight
(b) get twisted
(c) will bend with aluminium on concave side
(d) will bend with steel on concave side

D

Question. A uniform metallic rod rotates about its perpendicular bisector with constant angular speed. If it is heated uniformly to raise its temperature slightly
(a) its speed of rotation increases
(b) its speed of rotation decreases
(c) its speed of rotation remains same
(d) its speed increases because its moment of inertia increases

B

Question. An aluminium sphere is dipped into water. Which of the following is true?
(a) Buoyancy will be less in water at 0°C than that in water at 4°C
(b) Buoyancy will be more in water at 0°C than that in water at 4°C
(c) Buoyancy in water at 0°C will be same as that in water at 4°C
(d) Buoyancy may be more or less in water at 4°C depending on the radius of the sphere

A

Question. As the temperature is increased, the period of a pendulum
(a) increases as its effective length increases even though its centre of mass still remains at the centre of the bob
(b) decreases as its effective length increases even though its centre of mass still remains at the centre of the bob
(c) increases as its effective length increases due to shifting to centre of mass below the centre of the bob
(d) decreases as its effective length remains same but the centre of mass shifts above the centre of the bob

A

Question6. Heat is associated with
(a) kinetic energy of random motion of molecules
(b) kinetic energy of orderly motion of molecules
(c) total kinetic energy of random and orderly motion of molecules
(d) kinetic energy of random motion in some cases and kinetic energy of orderly motion in other