CBSE Class 11 Physics Thermal Properties Of Fluids Worksheet

Question. A beaker contains 200 g of water. The heat capacity of beaker is equal to that 20 g of water. The initial temperature of water in the beaker is 20°C . If 440 g of hot water at 92°C is poured in, the final temperature, neglecting radiation loss, will be
(a) 58°C
(b) 68°C
(c) 73°C
(d) 78°C

Answer: B

Question. The graph between two temperature scales A and B is shown in figure between upper fixed point and lower fixed point there are 150 equal division on scale A and 100 on scale B. The relationship for conversion between the two scales is given by 

Answer: B

Question. 5 kg of water at 10°C is added to 10 kg of water at 40°C. Neglecting heat capacity of vessel and other losses, the equilibrium temperature will be
(a) 30°C
(b) 25°C
(c) 35°C
(d) 33°C

Answer: A

Question. A glass flask of volume 1 litre is fully filled with mercury at 0ºC. Both the flask and mercury are now heated to 100ºC. If the coefficient of volume expansion of mercury is 1.82 × 10^{– 4}/ºC, volume coefficient of linear expansion of glass is 10 × 10^–6/ºC, the amount of mercury which is spilted out is
(a) 15.2 ml
(b) 17.2 ml
(c) 19.2 ml
(d) 21.2 ml

Answer: A

Question. 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

Answer: A

Question. Two rods of same length and transfer a given amount of heat 12 second, when they are joined as shown in figure (i). But when they are joined as shwon in figure (ii), then they will transfer same heat in same conditions in

(a) 24 s
(b) 13 s
(c) 15 s
(d) 48 s

Answer: D

Question. A slab consists of two parallel layers of copper and brass of the same thickness and having thermal conductivities in the ratio 1 : 4. If the free face of brass is at 100°C and that of copper at 0°C, the temperature of interface is
(a) 80°C
(b) 20°C
(c) 60°C
(d) 40°C

Answer: A

Question. The radius of a metal sphere at room temperature T is R and the coefficient of linear expansion of the metal is a. The sphere heated a little by a temperature DT so that its new temperature is T + DT. The increase in the volume of the sphere is approximately.
(a) 2πRαΔT
(b) pR2αΔT
(c) 4πR³αΔT / 3
(d) 4πR³αΔT

Answer: D

Question. Two metal rods 1 and 2 of same lengths have same temperature difference between their ends. Their thermal conductivities are K₁ and K₂ and cross sectional areas A₁ and A₂, respectively. If the rate of heat conduction in rod 1 is four times that in rod 2, then 
(a) K₁A₁ = K₂A₂
(b) K₁A₁ = 4K₂A₂
(c) K₁A₁ = 2K₂A₂
(d) 4K₁A₁ = K₂A₂

Answer: B

Question. A rectangular block is heated from 0ºC to 100ºC. The percentage increase in its length is 0.10%. What will be the percentage increase in its volume?
(a) 0.03%
(b) 0.10%
(c) 0.30%
(d) None of these

Answer: C

Question. The rectangular surface of area 8 cm × 4 cm of a black body at temperature 127°C emits energy E per second. If the length and breadth are reduced to half of the initial value and the temperature is raised to 327°C, the rate of emission of energy becomes
(a) 3/8 E
(b) 81/16 E
(c) 9/16 E
(d) 81/64 E

Answer: D

Question. Certain quantity of water cools from 70°C to 60°C in the first 5 minutes and to 54°C in the next 5 minutes. The temperature of the surroundings is:
(a) 45°C
(b) 20°C
(c) 42°C
(d) 10°C

Answer: A

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) 16.8 J/s
(b) 8.0 J/s
(c) 4.0 J/s
(d) 44.0 J/s

Answer: C

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

Answer: A

Question. A body of mass 5 kg falls from a height of 20 metres on the ground and it rebounds to a height of 0.2 m. If the loss in potential energy is used up by the body, then what will be the temperature rise? (specific heat of material = 0.09 cal gm^–1 ºC^–1)
(a) 0ºC
(b) 4ºC
(c) 8ºC
(d) None of these

Answer: D

Question. The value of coefficient of volume expansion of glycerine is 5 × 10-4 K-1. The fractional change in the density of glycerine for a rise of 40°C in its temperature, is: 
(a) 0.020
(b) 0.025
(c) 0.010
(d) 0.015

Answer: A

Question. A bimetallic strip is made of aluminium and steel (α_Al > asteel). 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

Answer: 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

Answer: 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

Answer: B

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

Answer: 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

Answer: C

Question. A crystal has a coefficient of expansion 13×10^–7 in one direction and 231 × 10^–7 in every direction at right angles to it. Then the cubical coefficient of expansion is
(a) 462 × 10^–7
(b) 244 × 10^–7
(c) 475 × 10^–7
(d) 257 × 10^–7

Answer: A

Question. In a thermocouple, the temperature of the cold junction and the neutral temperature are –40°C and 275°C respectively. If the cold junction temperature is increased by 60°C, the neutral temperature and temperature of inversion respectively become
(a) 275°C, 530°C
(b) 355°C, 530°C
(c) 375°C, 590°C
(d) 355°C, 590°C

Answer: A

Question. Two vessels of different materials are similar in size in every respect. The same quantity of ice filled in them gets melted in 20 min and 35 min, respectivley. The ratio of coefficients of thermal conduction of the metals is
(a) 4 : 7
(b) 7 : 4
(c) 25 : 16
(d) 16 : 25

Answer: B

Question. 80 g of water at 30ºC are poured on a large block of ice at 0ºC. The mass of ice that melts is
(a) 1600 g
(b) 30 g
(c) 150 g
(d) 80 g

Answer: B

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

Answer: A

Question. In a surrounding medium of temperature 10°C, a body takes 7 min for a fall of temperature from 60°C to 40°C. In what time the temperature of the body will fall from 40°C to 28°C?
(a) 7 min
(b) 11 min
(c) 14 min
(d) 21 min

Answer: A

Question. Three identical rods A, B and C of equal lengths and equal diameters are joined in series as shown in figure. Their thermal conductivities are 2k, k and k/2 respectively. The temperatures at two junction points are
(a) 85.7, 57.1°C
(b) 80.85, 50.3°C
(c) 77.3, 48.3°C
(d) 75.8, 49.3°C

Answer: A

Question. The rate of heat flow through the cross-section of the rod shown in figure is (T₂ > T₁ and thermal conductivity of the material of the rod is K) 

Answer: A

Question. A metallic bar is heated from 0ºC to 100ºC. The coeficient of linear expansion is 10–5 K^–1. What will be the percentage increase in length?
(a) 0.01%
(b) 0.1%
(c) 1%
(d) 10%

Answer: B

Question. Ice starts forming in a lake with water at 0ºC when the atomspheric temperature is –10ºC. If the time taken for the first 1 cm of ice to be formed is 7 hours, then the time taken for the thickness of ice to change from 1 cm to 2 cm is
(a) 7 hours
(b) 14 hours
(c) 21 hours
(d) 3.5 hours

Answer: C

Question. Two identical rods of copper and iron are coated with wax uniformly. When one end of each is kept at temperature of boiling water, the length upto which wax melts are 8.4 cm amd 4.2 cm, respectively. If thermal conductivity of copper is 0.92, then thermal conductivity of iron is
(a) 0.23
(b) 0.46
(c) 0.115
(d) 0.69

Answer: A

Question. The thermal capacity of 40g of aluminium (specific heat = 0.2 cal g^–1 °C^–1) is
(a) 40 cal °C^–1
(b) 160 cal °C^–1
(c) 200 cal °C^–1
(d) 8 cal °C^–1

Answer: D

Question. Two rods A and B of different materials are welded together as shown in figure. Their thermal conductivities are K₁ and K₂. The thermal conductivity of the composite rod will be : 

(a) 3(K₁ + K₂)/2
(b) K₁ + K₂
(c) 2 (K₁ + K₂)
(d) K₁ + K₂/2

Answer: D

Question. The density of water at 20°C is 998 kg/m3 and at 40°C 992 kg/m3. The coefficient of volume expansion of water is
(a) 10^–4/°C
(b) 3 × 10^–4/°C
(c) 2 × 10^–4/°C
(d) 6 × 10^–4/°C

Answer: B

Question. Which of the following temperatures is the highest?
(a) 100K
(b) –13°F
(c) –20°C
(d) –23°C.

Answer: B

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

Answer: D

Question. A partition wall has two layers A and B, in contact, each made of a different material. They have the same thickness but the thermal conductivity of layer A is twice that of layer B. If the steady state temperature difference across the wall is 60 K, then the corresponding difference across the layer A is
(a) 10 K
(b) 20 K
(c) 30 K
(d) 40 K

Answer: B

Question. A sphere, a cube and a thin circular plate, all of same material and same mass are initially heated to same high temperature.
(a) Plate will cool fastest and cube the slowest
(b) Sphere will cool fastest and cube the slowest
(c) Plate will cool fastest and sphere the slowest
(d) Cube will cool fastest and plate the slowest

Answer: C

Question. On observing light from three different stars P, Q and R, it was found that intensity of violet colour is maximum in the spectrum of P, the intensity of green colour is maximum in the spectrum of R and the intensity of red colour is maximum in the spectrum of Q. If TP, TQ and TR are the respective absolute temperature of P, Q and R, then it can be concluded from the above observations that
(a) TP > TR > TQ
(b) TP < TR < TQ
(c) TP < TQ < TR
(d) TP > TQ > TR

Answer: A

Question. A bucket full of hot water is kept in a room and it cools from 75ºC to 70ºC in T₁ minutes, from 70ºC to 65ºC in T₂ minutes and from 65ºC to 60ºC in T₃ minutes. Then
(a) T₁ = T₂ = T₃
(b) T₁ < T₂ < T₃
(c) T₁ > T₂ > T₃
(d) T₁ < T₂ > T₃

Answer: 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) Wien’s displacement law
(b) Kirchoff’s law
(c) Newton’s law of cooling
(d) Stefan’s law

Answer: A

Question. Which one of the following graphs best represents the ways in which the total power P radiated by a black body depends upon the thermodynamic temperature T of the body? 

Answer: C

Question. Two marks on a glass rod 10 cm apart are found to increase their distance by 0.08 mm when the rod is heated from 0°C to 100°C. A flask made of the same glass as that of rod measures a volume of 1000 cc at 0°C. The volume it measures at 100°C in cc is
(a) 1002.4
(b) 1004.2
(c) 1006.4
(d) 1008.2

Answer: A

DIRECTIONS for These are Assertion-Reason type questions. Each of these question contains two statements:
Statement-1 (Assertion) and Statement-2 (Reason). Answer these questions from the following four options.
(a) Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement -1
(b) Statement-1 is True, Statement -2 is True; Statement-2 is NOT a correct explanation for Statement - 1
(c) Statement-1 is True, Statement- 2 is False
(d) Statement-1 is False, Statement -2 is True

Question. Statement 1 : The equivalent thermal conductivity of two plates of same thickness in series is less than the smaller value of thermal conductivity.
Statement 2 : For two plates of equal thickness in series the equivalent thermal conductivity is given by 1/K = 1/K₁ + 1/K₂ .

Answer: A

Question. Statement 1 : As the temperature of the black body increases, the wavelength at which the spectral intensity (E_λ) is maximum decreases.
Statement 2 : The wavelength at which the spectral intensity will be maximum for a black body is proportional to the fourth power of its absolute temperature.

Answer: C

Question- Good absorbers of heat are

(a) poor emitters

(b) non-emitters

(c) good emitters

(d) highly polished

Answer-(c)

Question-Which of the following is not a unit of heat energy ?

(a) joule

(b) kelvin

(c) calorie

(d) None of these

Answer-(b)

Question-Mass of water which absorbs or emits the same amount of heat as is done by the body for the same rise or fall in temperature is known as

(a) thermal capacity of the body

(b) specific heat capacity of the body

(c) latent heat capacity of the body

(d) water equivalent of the body

Answer-(d)

Question-Newton’s law of cooling is applicable for

(a) any excess of temperature over the surrounding.

(b) small excess of temperature over the surrounding.

(c) large excess of temperature over the surrounding.

(d) very large excess of temperature over the surrounding.

Answer-(b)

Question-When water is heated from 0ºC to 4ºC, its volume

(a) increases

(b) decreases

(c) does not change

(d) first decreases and then increases

Answer-(d)

Question-Heat is transmitted from higher to lower temperature through actual mass motion of the molecules in

(a) conduction

(b) convection

(c) radiation

(d) None of these

Answer-(b)

Question-Triple point of water is

(a) 273.16°F

(b) 273.16 K

(c) 273.16°C

(d) 273.16 R

Answer-(b)

Question- Sweet makers do not clean the bottom of cauldron because

(a) emission power of black and bright surface is more.

(b) absorption power of black and bright surface is more.

(c) black and rough surface absorbs more heat.

(d) transmission power of black and rough surface is more.

Answer-(c)

Question-Which of the following will expand the most for same rise in temperature?

(a) Aluminium

(b) Glass

(c) Wood

(d) All will expand same

Answer-(a)

Question-Which of the following is a poor conductor of heat ?

(a) Copper

(b) Concrete

(c) Mercury

(d) Air

Answer-(d)

Question- Which of the following is the unit of specific heat

(a) J kg°C^–1

(b) J/kg°C

(c) kg°C/J

(d) J/kg°C^–2

Answer-(b)

Question-Heat content of a body depends on

(a) mass of the body

(b) temperature of the body

(c) specific heat capacity

(d) all of the above

Answer-(d)

Question- Which of the following undergo sublimation ?

(a) Dry ice

(b) Iodine

(c) Both (a) and (b)

(d) None of these

Answer-(c)

Question-Which of the following pairs may give equal numerical values of the temperature of a body?

(a) Fahrenheit and Celsius

(b) Celsius and Kelvin

(c) Kelvin and Reaumur

(d) None of these

Answer-(a)

Question- The value of molar heat capacity at constant temperature is

(a) zero

(b) infinity

(c) unity

(d) 4.2

Answer-(b)

Question- Expansion during heating

(a) occurs only in solids

(b) increases the weight of a material

(c) generally decreases the density of a material

(d) occurs at the same rate for all liquids and solids

Answer-(c)

Question- 4200 J of work is required for

(a) increasing the temperature of 10 g of water through 10°C

(b) increasing the temperature of 100 g of water through 10°C

(c) increasing the temperature of 1 kg of water through 10°C

(d) increasing the temperature of 10 g of water through 10°C

Answer-(b)

Question- The latent heat of vaporization of a substance is always

(a) greater than its latent heat of fusion

(b) greater than its latent heat of sublimation

(c) equal to its latent heat of sublimation

(d) less than its latent heat of fusion

Answer-(a)

Question- Which of the following is used as a coolent in automobile radiator as well as a heater in hot water bags?

(a) Ice

(b) Sand

(c) Water

(d) All of these

Answer-(c)

Question- The reading of Centigrade thermometer coincides with that of Fahrenheit thermometer in a liquid. The temperature of the liquid is

(a) – 40ºC

(b) 313°C

(c) 0°C

(d) 100°C

Answer-(a)

Question- Which law is obeyed when temperature difference between the body and the surroundings is small?

(a) Stefan’s law

(b) Newton’s law of cooling

(c) Planck’s law

(d) All of these

Answer-(b)

Question- Three bodies A, B and C have equal area which are painted red, yellow and black respectively. If they are at same temperature, then

(a) emissive power of A is maximum.

(b) emissive power of B is maximum.

(c) emissive power of C is maximum.

(d) emissive power of A, B and C are equal.

Answer-(c)

Question- Lamp black absorbs radiant heat which is near about

(a) 90%

(b) 98%

(c) 100%

(d) 50%

Answer-(b)

Question- ... A... and ...B... of heat energy required some material as a transport medium. Hear, A and B refer to

(a) conduction, radiation

(b) radiation, convection

(c) conduction, convection

(d) radiation, evaporation

Answer-(c)

Question- 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) None of these

Answer-(a)

Question- A quantity of heat required to change the unit mass of a solid substance, from solid state to liquid state, while the temperature remains constant, is known as

(a) latent heat

(b) sublimation

(c) hoar frost

(d) latent heat of fusion

Answer-(d)

Question- Newton’s law of cooling is also applicable to

(a) convection losses.

(b) natural convection losses.

(c) forced convection losses.

(d) conduction losses.

Answer-(c)

Question- The phenomenon of refreezing the water into ice on removing the increased pressure is called

(a) freezing

(b) fusion

(c) sublimation

(d) regelation

Answer-(d)