Heat and Thermodynamics – Old Year Questions

1. Transfer of heat by convection can take place in

(a) Solids and liquids
(b) Solids and vacuum
(c) Gases and liquids
(d) Vacuum and gases

[M.P.P.C.S. (Pre) 2017]

2. A liquid remains hot or cold for a long time in thermos fask because there is no loss or gain of heat by

(a) Conduction
(c) Both (a) and (b)
(d) None of the above

[U.P.P.C.S. (Pre) 2019]

3. Steam at 100ºC causes more severe burns than the water at the same temperature, because :

(a) Steam is a gas
(b) Steam provides more heat
(c) Steam is highly combustible
(d) Steam exerts more pressure

Chhattisgarh P.C.S. (Pre) 2008

4. The hand burns more by steam comparatively to boiling water, because –

(a) The steam has latent heat
(b) Steam sneaked into the body
(c) The steam has more power
(d) Steam is a gig

U.P. P.C.S. (Pre) 1993

5. The heat required in calories to convert one gram of ice at 0° C to steam at 100° C is approximately

(a) 80
(b) 336
(c) 720
(d) 620

[Uttarakhand Lower Sub. (Pre) 2010]

6. At what temperature are the reading of a Centigrade and Fahrenheit thermometer the same?

(a) –40
(b) 212
(c) 40
(d) 100

[U.P.P.C.S. (Mains) 2015, U.P. U.D.A/L.D.A. (Pre) 2003, I.A.S. (Pre) 1993]

7. To what degree are the Centigrade and Fahrenheit temperatures the same?

(a) 100°
(b) 80°
(c) –32°
(d) –40°

[M.P.P.C.S. (Pre) 1994, M.P.P.C.S. (Pre) 1995]

8. At which temperature, do the Celsius and Fahrenheit scales coincide?

(a) 0°
(b) 10°
(c) –40°
(d) 40°
(e) None of the above/More than one of the above

[66th B.P.S.C. (Pre) (Re. Exam) 2020]

9. At what point the Fahrenheit temperature is double of centigrade temperature?

(a) –6.7o C
(b) –12.3o C
(c) 12.3o C
(d) 160o C

[R.A.S./R.T.S.(Pre) 2007]

10. The body temperature of a healthy man is –

(a) 37° Celsius
(b) 37° Fahrenheit
(c) 98.4° Celsius
(d) 98.4° Kelvin

[Uttarakhand P.C.S. (Pre) 2005]

11. The normal temperature of the human body on the Kelvin scale is –

(a) 280
(b) 290
(c) 300
(d) 310

[I.A.S. (Pre) 1995]

12. The normal temperature of the human body is 98.4°F. It’s the equivalent temperature in °C is –

(a) 40.16
(b) 36.89
(c) 35.72
(d) 32.36

[U.P.P.C.S. (Pre) (Re. Exam) 2015]

13. Normal temperature of the human body on a Celsius scale will be –

(a) 310 degree
(b) 98.4 degree
(c) 36.9 degree
(d) 31.5 degree

[41st B.P.S.C. (Pre) 1996]

14. Which one of the following scales of temperature does not have a negative value?

(a) Celsius
(b) Fahrenheit
(c) Kelvin
(d) Reaumur

[U.P. R.O./A.R.O. (Pre) 2017]

15. A measured temperature in Fahrenheit scale is 200ºF. What will be its value in Celsius scale?

(a) 93.3ºC
(b) 40ºC
(c) 99ºC
(d) 30ºC

[U.P.B.E.O. (Pre) 2019]

16. The value of 40 degrees Celsius in Fahrenheit scale is

(a) 104º F
(b) 100º F
(c) 102º F
(d) 75º F
(e) None of the above / More than one of the above

[64th B.P.S.C. (Pre) 2018]

17. The value of 50° C on the Fahrenheit scale is

(a) 104°F
(b) 122°F
(c) 100°F
(d) 75°F
(e) None of the above/More than one of the above

[65th B.P.S.C. (Pre) 2019]

18. In cold countries, alcohol is preferred to mercury as a thermometric liquid because :

(a) Alcohol has a lower freezing point
(b) Alcohol is a better conductor of heat
(c) Alcohol is cheaper than mercury
(d) The world production of alcohol is greater than that of mercury

[U.P.P.C.S. (Pre) 1997]

19. Which one of the following is used as an antifreeze for the automobile engines ?

(a) Ethanol
(b) Ethylene glycol
(c) Methanol
(d) Propyl alcohol

[U.P.P.C.S. (Spl.) (Pre) 2008, U.P. U.D.A./L.D.A. (Mains) 2010]

20. What is absolute zero temperature?

(a) The starting point of any temperature scale
(b) Theoretically the lowest possible temperature.
(c) The temperature at which the vapour of any liquid substance is condensed.
(d) The temperature at which all material are in vapour form.

[Jharkhand P.C.S. (Pre) 2010]

21. Expansion during heating –

(a) Occurs only in solid
(b) Increases the weight of the material
(c) Decreases the density of the material
(d) Occurs at the same rate for all liquids and solids

[U.P.P.C.S. (Pre) 2006]

22. When ice melts, then-

(a) Volume increases
(b) Volume decreases
(c) Mass increases
(d) Mass decreases

[U.P.P.C.S. (Pre) 2012]

23. The variations in temperature from 0° C to 100° C with respect to the time of two liquids P and, Q are shown in the graph given below:

Which of the following statements is correct?

(a) During heating, liquid P is always warmer than Q.
(b) At no point of time during heating did the two liquids have the same temperature.
(c) P attained the temperature of 100o C faster than Q.
(d) Q attained the temperature of 100o C faster than P.

[I.A.S. (Pre) 1995]

24. What is the use of thermostat?

(a) To measure the temperature
(b) To increase the temperature
(c) To maintain the temperature
(d) To convert heat into electricity

[M.P.P.C.S. (Pre) 2005]

25. Thermostat is related to :

(a) Humidity
(b) Temperature
(c) Air
(d) Clouds

[U.P.P.C.S. (Pre) 1993]

26. Thermostat is a device which :

(a)Measures heat
(b)Measures temperature
(c)Automatically regulates the temperature of a system
(d)Automatically regulates the pressure of a system

[U.P.P.C.S. (Pre) 2007]

27. Thermostat …………. is a means of keeping stable?

(a) Current
(b) Temperature
(c) Pressure

[Chhattisgarh P.C.S. (Pre) 2003]

28. What is the function of the thermostat of a refrigerator?

(a) To lower the temperature
(b) To increase the freezing point
(c) To maintain constant temperature
(d) To decrease the melting point

[U.P.P.C.S. (Pre) 1996]

29. The safest temperature for keeping food fresh in a refrigerator is

(a) 4°C
(b) 8°C
(c) 0°C
(d) 10°C

[U.P.P.C.S. (Pre) 2007]

30. When soggy biscuits are kept inside the fridge for sometimes they become crisp because :

(a) Cooling releases extra moisture
(b) Humidity inside the fridge is low and extra moisture is absorbed.
(c) Humidity inside the fridge is high and extra moisture is absorbed.
(d) Pressure inside the fridge is high and help in releasing extra moisture.

[U.P.P.C.S. (Pre) 2009]

31. Assertion (A): A piece of ice is added to the drink, and cools it.
Reason (R): Ice takes latent heat from the drink for melting resulting in the cooling of the drink.

Select the correct answer using the codes given below:

(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

[U.P. Lower Sub. (Pre) 2009]

32. Assertion (A): Large cold storage plants use ammonia as refrigerant while domestic refrigerators use chlorofluorocarbons.
Reason (R): Ammonia can be liquefied at ambient temperatures at low pressures.

Code :
(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

[I.A.S. (Pre) 2000]

33. Consider the following statements –

Assertion (A): If Ice collects in the freezer, the cooling in the refrigerator is afected adversely.
Reason (R): Ice is a poor conductor.

Select the correct answer using the codes given below:

Code :
(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

[U.P.P.C.S (Pre) 2010]

34. When a glass rod is placed in steam, its length increases but its width :

(a) Remains unchanged
(b) Decreases
(c) Increases
(d) Becomes irregular

[U.P.P.C.S. (Pre) 1994]

35. Consider the figures of a metal ball and a metal ring given below :

The metal ball can just pass through the hole of a metal ring formed out of a strip. When the ball is heated it gets stuck. But when the metal is heated-

(a) The ball can still pass through the ring as the diameter expands on heating.
(b) The ball gets stuck because the diameter of the hole decreases on expansion.
(c) The ball will still pass through because the hole diameter does not change.
(d) The ball will pass through because there is no change in the ring.

[I.A.S. (Pre) 1993]

36. Assertion (A): A piece of copper and a piece of glass are heated to the same temperature. When touched, thereafter, the copper piece appears hotter than the glass piece.
Reason (R): The density of copper is more than that of glass.

Code :

(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not a correct explanation of A
(c) A is true but R is false
(d) A is false but R is true

[I.A.S. (Pre) 2001]

37. In winter you touch a log of wood and a rod of iron, you will feel rod of iron is colder because –

(a) The heat of rod of iron is less than the heat of log of wood
(b) In comparison to wood, iron is good conductor of heat
(c) In comparison to wood, iron is bad conductor of heat
(d) The rod of iron is heavier than the log of wood

[41st B.P.S.C. (Pre) 1996]

38. If the temperature of air increases, how would it afect its ability to assume water vapour-

(a) Decrease
(b) Increase
(c) Firstly decrease, then again increase
(d) Remains constant

[Jharkhand P.C.S. (Pre) 2003]

39. In the night of strong wind, dew is not formed because

(a) The rate of evaporation is fast
(b) Moisture in air is low
(c) Temperature is high
(d) Sky is not clear

[40th B.P.S.C. (Pre) 1995]

40. Which of the following statements is not true?

(a) Air-conditioner and Air-Cooler both maintain temperature.
(b) Air-Conditioner and Air-Cooler both maintain humidity
(c) Air-Conditioner maintains humidity but Air-Cooler does not maintain humidity
(d) Both control motion of air

[U.P.P.C.S. (Pre) 2007]

41. What does an air conditioner installed in a room control?

(a) Temperature only
(b) Humidity and temperature only
(c) Pressure and temperature only
(d) Humidity, pressure, and temperature

[U.P.P.C.S. (Mains) 2011]

42. The cooling by a desert cooler is based on –

(a) Hot air replacement
(b) Air dehydration
(c) Evaporative cooling
(d) Air rehydration

[R.A.S./R.T.S.(Pre) 2012]

43. Cooling is done by –

(a) Flow of water
(b) Release of compressed gas
(c) Cooking gas
(d) Melting the solid

[47th B.P.S.C. (Pre) 2005]

44. In which of the following conditions wet clothes will dry earliest?

(a) 100% RH, 60° C temperature
(b) 100% RH, 20°C temperature
(c) 20% RH, 20°C temperature
(d) 20% RH, 60°C temperature

[U.P.P.C.S. (Pre) 2008]

45. Which one of the following changes occurs when salt is added into the water?

(a) Boiling point is increased and freezing point decreased
(b) Boiling point is decreased and freezing point is increased
(c) Both boiling point and freezing point are decreased
(d) Both boiling point and freezing point are increased

[R.A.S./R.T.S.(Pre) 2008]

46. On adding common salt to water, the boiling point and freezing point of water will :

(a) Increase
(b) Decrease
(c) Decrease and increase respectively
(d) Increase and decrease respectively

[U.P.P.C.S. (Mains) 2006]

47. An assertion and its reason is given below –

Assertion (A): Salt is used for cooking the food at places on higher from sea level .
Reason (R): Temperature is low in higher places.

Which one among these is right answer?

(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

[Uttarakhand P.C.S. (Pre) 2012]

48. To keep drinks at the same temperature for quite sometime, the walls of thermos bottle are coated with :

(a) Aluminium paint
(c) Silver layer
(d) Mercury Layer

[R.A.S./R.T.S. (Pre) 1996]

49. It is more comfortable to wear white cloth in summer because

(a) They reflect all the heat falling on them
(b) They radiate heat transferred from the body
(c) They absorb perspiration
(d) They are soothing to the eye

[U.P.P.C.S. (Pre) 2007]

50. White clothes are cooler than black clothes because :

(a) They absorb whole of light
(b) They inhibit penetration of light
(c) They make sunlight completely cool
(d) They reflect the whole light

[U.P. R.O./A.R.O. (Mains) 2016]

51. Assertion and Reason are given below –

Assertion (A): We prefer the white dress in winter.
Reason (R): White dresses are good reflectors of heat.

Which one among these is the right answer?

(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

[Uttarakhand P.C.S. (Pre) 2012]

52. Consider the following statements :

Assertion (A) : Light coloured clothes are preferred in summer.
Reason (R) : Light colours are poor absorbers of heat.

Select correct answer from the code given below :

(a) Both (A) and (R) are correct and (R) correctly explains (A).
(b) Both (A) and (R) are correct, but (R) does not correctly explain (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

[U.P. R.O./A.R.O. (Pre) 2016]

53. Loss of water from the body through perspiration depends on :

(a) Atmospheric temperature only
(b) Atmospheric humidity only
(c) Both (a) and (b)
(d) None of (a) and (b)

[U.P. B.E.O. (Pre) 2019]

54. The most important function of perspiration is to :

(a) Regulate body temperature
(b) Regulate body water supply
(c) Get rid of body poison.
(d) Keep the skin pores clear of dirt.

[R.A.S./R.T.S. (Pre) 1994-95]

55. A fan produces a feeling of comfort during hot weather, because –

(a) Fan supplies cold air
(b) Our perspiration evaporates rapidly
(c) Our body radiates more heat
(d) Conductivity of air increase

[M.P.P.C.S. (Pre) 2008]

56. In an earthen pitcher, the water remains cold due to the process of

(a) Condensation
(b) Evaporation
(c) Sublimation
(d) None of the above

[U.P.P.C.S.(Pre) 2012]

57. On a specific day and time, the temperature was 48o C in Churu and 24° C in Shimla. Two metallic cups identical in all respects contained water at 95° C in Churu and 71° C in Shimla.

Which one of these two cups reached room temperature first?

(a) Cup in Churu
(b) Cup in Shimla
(c) Both cups reached room temperature at the same time
(d) Data are not enough to find out result

[R.A.S./R.T.S.(Pre) 2008]

58. A hot body cools from 90º C to 75º C in 25 seconds. The same body in further cooling from 75º C to 60º C will take how much time?

(a) 25 seconds
(b) Less than 25 seconds
(c) More than 25 seconds
(d) Nothing can be said

[U.P.P.C.S. (Mains) 2017]

59. In the season of summer, we experience a humid heat when weather :

(a) Start of summer
(b) Middle of summer
(c) Scorching weather
(d) Humid weather

[U.P. P.C.S. (Pre) 2003]

60. Xeric condition refers to –

(a) low temperature
(b) low humidity
(c) high evaporation
(d) extreme temperature

[U.P.R.O/A.R.O. (Pre) 2014]

61. The atmosphere exerts enormous pressure on us. But, we do not feel it because

(a) Our blood exerts a pressure slightly more than that of the atmosphere.
(b) We are used to it.
(c) Our bones are very strong and can withstand the pressure.
(d) The surface area of our head is very small.

[U.P.P.C.S (Pre) 2010]

62. Assertion (A): The boiling point of water decreases as the altitude increases.
Reason (R): The atmospheric pressure increases with altitude.

Code :
(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

[I.A.S. (Pre) 2001]

63. Food gets cooked faster in a pressure cooker because –

(a) Water starts boiling at a lower temperature due to high pressure
(b) Water starts boiling at a higher temperature due to high pressure
(c) Water boils only at 100oC but the heat content is higher at high pressure
(d) Convection currents are set inside the cooker

[U.P.P.C.S. (Pre) 2007]

64. Pressure-cooker cooks food in less time because

(a) The temperature of boiling water decreases due to high pressure
(b) Air has no effect as it is closed from all sides
(c) Temperature of boiling water increases due to high pressure
(d) Evaporation of the water used is very small

[Uttarakhand P.C.S. (Pre) 2005]

65. Why does food cook faster in a pressure cooker?

(a) The increased pressure increases the boiling point.
(b) Does not waste steam.
(c) The food is cooked quickly by steam.
(d) The water boils at constant temperature.

[U.P. Lower Sub. (Pre) 2002]

66. Food is cooked faster in a pressure cooker because

(a) Heat cannot escape from the cooker.
(b) Steam is colder than the boiling water.
(c) Due to high pressure, the boiling point of water is raised.
(d) Water starts boiling at a lower temperature.

[Uttarakhand Lower Sub. (Pre) 2010]

67. Assertion (A): The handle of the pressure cooker is made up of Ebonite.
Reason (R): Ebonite is a hard material.

Code :

(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

[Uttarakhand P.C.S. (Pre) 2012]

68. Maximum temperature inside pressure cooker depends on :

(a) Area of hole on the top and weight kept on it
(b) Area of hole on the top and food being cooked
(c) Weight kept on hole at top and food being cooked
(d) Area of hole on the top only

[U.P.P.C.S. (Pre) 1995]

69. When water is heated from 0°C to 10°C. It’s volume :

(a) Increases
(b) Decreases
(c) Does not change
(d) First decreases and then increases

[I.A.S. (Pre) 2001]

70. What changes will the volume of water show if the temperature is lowered from 9°C to 3°C :

(a) The volume will not change
(b) The volume will first increase and then decrease
(c) The volume will first decrease and then increase
(d) Water will freeze

[U.P.P.C.S. (Pre) 1997]

71. Consider the following statements :

1. Steam at 100°C and boiling water at 100°C contain same amount of heat.
2. The latent heat of fusion of ice is equal to the latent heat of vaporization of water.
3. In an air-conditioner, heat is extracted from the room air at the evaporator coils and is ejected out at the condenser coils.

Which of these statements is/are correct?

(a) 1 and 2
(b) 2 and 3
(c) Only 2
(d) Only 3

[I.A.S. (Pre) 2003]

72. When a bottle is filled with water and it is freezing the bottle breaks down, because-

(a) Water expands upon freezing.
(b) Bottle shrinks at freezing point.
(c) The temperature outside the bottle is higher than inside.
(d) Water expands on heating.

[U.P.P.C.S. (Pre) 1995]

73. A glass bottle containing water tightly corked breaks when it is kept in freezer, because –

(a) Bottle shrinks on freezing.
(b) The volume of water decreases on freezing
(c) The volume of water increases on freezing.
(d) Glass is the bad conductor of heat.

[I.A.S. (Pre) 1994]

74. When a piece of ice floating in a glass of water melts, the level of water will :

(a) Fall
(b) Rise
(c) Remain same
(d) Fall or rise depends on the temperature of water

[R.A.S./R.T.S.(Pre) 2007]

75. Cloudy nights are warmer compared to clear cloudless nights, because clouds-

(a) Prevent cold waves from the sky from descending on earth.
(b) Refect back the heat given of by earth.
(c) Produce heat and radiate it towards earth.
(d) Absorb heat from the atmosphere and send it toward earth.

[I.A.S. (Pre) 2003]

76. The cloudy nights are warmer than clear nights because–

(a) The clouds prevent radiation of heat from the ground and the air
(b) Clouds absorb sunlight during the day and radiate the same in night
(c) Clouds make the atmosphere damp and generate heat
(d) The clouds obstruct the movement of air which creates heat

[U.P. Lower Sub. (Spl.) (Pre) 2008]

77. Fruit stored in a cold chamber exhibit longer storage life because

(a) Exposure to sunlight is prevented
(b) Concentration of carbon dioxide in environment is increases
(c) Rate of respiration is decreased
(d) There is increase in humidity

[I.A.S. (Pre) 2013]

78. Assertion (A): Woollen clothes keeps us warm.
Reason (R): Woollen fibres are made from a special type of protein, which is a bad conductor of heat.

Select the correct answer from the codes given below:

(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

[U.P.P.C.S. (Pre) 2001]

79. Which one of the following statements is not correct?

(a) The velocity of sound in air increases with the increase of temperature
(b) The velocity of sound in air is independent of pressure
(c) The velocity of sound in air decreases as the humidity increases
(d) The velocity of sound in air is not affected by the change in amplitude and frequency

[I.A.S. (Pre) 2003]

80. Opening the door of refrigerator kept in the room

(a) You can cool the room to some degree
(b) You can cool the room to the temperature of refrigerator
(c) You can warm the room a little
(d) You can neither cool nor warm the room

[39th B.P.S.C. (Pre) 1994]

81. If a gas is compressed to half of its original volume at 27°C, to what temperature should it be heated to make it occupy its original volume?

(a) 327°C
(b) 600°C
(c) 54°C
(d) 300°C

[I.A.S. (Pre) 1994]